diff --git a/bootctrl.h b/bootctrl.h
index 03da69b..61700b5 100644
--- a/bootctrl.h
+++ b/bootctrl.h
@@ -19,85 +19,86 @@
 #ifndef __BOOTCTRL_H__
 #define __BOOTCTRL_H__
 
+#include <stdbool.h>
+
 struct slot_info {
 	bool active;
 	bool bootable;
-        bool successful;
+	bool successful;
 };
 
 struct boot_control_module {
+	/*
+	* (*getCurrentSlot)() returns the value letting the system know
+	* whether the current slot is A or B. The meaning of A and B is
+	* left up to the implementer. It is assumed that if the current slot
+	* is A, then the block devices underlying B can be accessed directly
+	* without any risk of corruption.
+	* The returned value is always guaranteed to be strictly less than the
+	* value returned by getNumberSlots. Slots start at 0 and
+	* finish at getNumberSlots() - 1
+	*/
+	unsigned (*getCurrentSlot)();
 
-    /*
-     * (*getCurrentSlot)() returns the value letting the system know
-     * whether the current slot is A or B. The meaning of A and B is
-     * left up to the implementer. It is assumed that if the current slot
-     * is A, then the block devices underlying B can be accessed directly
-     * without any risk of corruption.
-     * The returned value is always guaranteed to be strictly less than the
-     * value returned by getNumberSlots. Slots start at 0 and
-     * finish at getNumberSlots() - 1
-     */
-    unsigned (*getCurrentSlot)();
-
-    /*
-     * (*markBootSuccessful)() marks the specified slot
-     * as boot successful
-     *
-     * Returns 0 on success, -errno on error.
-     */
-    int (*markBootSuccessful)(unsigned slot);
+	/*
+	* (*markBootSuccessful)() marks the specified slot
+	* as boot successful
+	*
+	* Returns 0 on success, -errno on error.
+	*/
+	int (*markBootSuccessful)(unsigned slot);
 
-    /*
-     * (*setActiveBootSlot)() marks the slot passed in parameter as
-     * the active boot slot (see getCurrentSlot for an explanation
-     * of the "slot" parameter). This overrides any previous call to
-     * setSlotAsUnbootable.
-     * Returns 0 on success, -errno on error.
-     */
-    int (*setActiveBootSlot)(unsigned slot);
+	/*
+	* (*setActiveBootSlot)() marks the slot passed in parameter as
+	* the active boot slot (see getCurrentSlot for an explanation
+	* of the "slot" parameter). This overrides any previous call to
+	* setSlotAsUnbootable.
+	* Returns 0 on success, -errno on error.
+	*/
+	int (*setActiveBootSlot)(unsigned slot);
 
-    /*
-     * (*setSlotAsUnbootable)() marks the slot passed in parameter as
-     * an unbootable. This can be used while updating the contents of the slot's
-     * partitions, so that the system will not attempt to boot a known bad set up.
-     * Returns 0 on success, -errno on error.
-     */
-    int (*setSlotAsUnbootable)(unsigned slot);
+	/*
+	* (*setSlotAsUnbootable)() marks the slot passed in parameter as
+	* an unbootable. This can be used while updating the contents of the slot's
+	* partitions, so that the system will not attempt to boot a known bad set up.
+	* Returns 0 on success, -errno on error.
+	*/
+	int (*setSlotAsUnbootable)(unsigned slot);
 
-    /*
-     * (*isSlotBootable)() returns if the slot passed in parameter is
-     * bootable. Note that slots can be made unbootable by both the
-     * bootloader and by the OS using setSlotAsUnbootable.
-     * Returns 1 if the slot is bootable, 0 if it's not, and -errno on
-     * error.
-     */
-    int (*isSlotBootable)(unsigned slot);
+	/*
+	* (*isSlotBootable)() returns if the slot passed in parameter is
+	* bootable. Note that slots can be made unbootable by both the
+	* bootloader and by the OS using setSlotAsUnbootable.
+	* Returns 1 if the slot is bootable, 0 if it's not, and -errno on
+	* error.
+	*/
+	int (*isSlotBootable)(unsigned slot);
 
-    /*
-     * (*getSuffix)() returns the string suffix used by partitions that
-     * correspond to the slot number passed in parameter. The returned string
-     * is expected to be statically allocated and not need to be freed.
-     * Returns NULL if slot does not match an existing slot.
-     */
-    const char* (*getSuffix)(unsigned slot);
+	/*
+	* (*getSuffix)() returns the string suffix used by partitions that
+	* correspond to the slot number passed in parameter. The returned string
+	* is expected to be statically allocated and not need to be freed.
+	* Returns NULL if slot does not match an existing slot.
+	*/
+	const char *(*getSuffix)(unsigned slot);
 
-    /*
-     * (*isSlotMarkedSucessful)() returns if the slot passed in parameter has
-     * been marked as successful using markBootSuccessful.
-     * Returns 1 if the slot has been marked as successful, 0 if it's
-     * not the case, and -errno on error.
-     */
-    int (*isSlotMarkedSuccessful)(unsigned slot);
+	/*
+	* (*isSlotMarkedSucessful)() returns if the slot passed in parameter has
+	* been marked as successful using markBootSuccessful.
+	* Returns 1 if the slot has been marked as successful, 0 if it's
+	* not the case, and -errno on error.
+	*/
+	int (*isSlotMarkedSuccessful)(unsigned slot);
 
-    /**
-     * Returns the active slot to boot into on the next boot. If
-     * setActiveBootSlot() has been called, the getter function should return
-     * the same slot as the one provided in the last setActiveBootSlot() call.
-     */
-    unsigned (*getActiveBootSlot)();
+	/**
+	* Returns the active slot to boot into on the next boot. If
+	* setActiveBootSlot() has been called, the getter function should return
+	* the same slot as the one provided in the last setActiveBootSlot() call.
+	*/
+	unsigned (*getActiveBootSlot)();
 };
 
 extern const struct boot_control_module bootctl;
 extern const struct boot_control_module bootctl_test;
 
-#endif  // __BOOTCTRL_H__
+#endif // __BOOTCTRL_H__
diff --git a/bootctrl_impl.cpp b/bootctrl_impl.c
similarity index 76%
rename from bootctrl_impl.cpp
rename to bootctrl_impl.c
index 0ff0af9..d6bd9d0 100644
--- a/bootctrl_impl.cpp
+++ b/bootctrl_impl.c
@@ -16,21 +16,18 @@
  * along with this program.  If not, see <http:// www.gnu.org/licenses/>.
  */
 
+#include <assert.h>
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
-#include <list>
-#include <map>
-#include <regex>
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
-#include <string>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
-#include <vector>
 
 #include "gpt-utils.h"
 #include "ufs-bsg.h"
@@ -57,7 +54,6 @@
 				(*(pentry + AB_FLAG_OFFSET) & ~AB_PARTITION_ATTR_SLOT_ACTIVE);     \
 	})
 
-using namespace std;
 const char *slot_suffix_arr[] = { AB_SLOT_A_SUFFIX, AB_SLOT_B_SUFFIX, NULL };
 
 enum part_attr_type {
@@ -98,12 +94,12 @@ error:
 }
 
 // Get the value of one of the attribute fields for a partition.
-static int get_partition_attribute(struct gpt_disk *disk, char *partname,
+static int get_partition_attribute(struct gpt_disk *disk, const char *partname,
 				   enum part_attr_type part_attr)
 {
-	uint8_t *pentry = nullptr;
+	uint8_t *pentry = NULL;
 	int retval = -1;
-	uint8_t *attr = nullptr;
+	uint8_t *attr = NULL;
 	if (!partname)
 		return -1;
 
@@ -151,13 +147,12 @@ static int update_slot_attribute(struct gpt_disk *disk, const char *slot,
 	unsigned int i = 0;
 	char buf[PATH_MAX];
 	struct stat st;
-	uint8_t *pentry = nullptr;
-	uint8_t *pentry_bak = nullptr;
+	uint8_t *pentry = NULL;
+	uint8_t *pentry_bak = NULL;
 	int rc = -1;
-	uint8_t *attr = nullptr;
-	uint8_t *attr_bak = nullptr;
+	uint8_t *attr = NULL;
+	uint8_t *attr_bak = NULL;
 	char partName[MAX_GPT_NAME_SIZE + 1] = { 0 };
-	static const char ptn_list[][MAX_GPT_NAME_SIZE - 1] = { AB_PTN_LIST };
 	int slot_name_valid = 0;
 	char devpath[PATH_MAX] = { 0 };
 
@@ -166,7 +161,7 @@ static int update_slot_attribute(struct gpt_disk *disk, const char *slot,
 		return -1;
 	}
 
-	for (i = 0; slot_suffix_arr[i] != nullptr; i++) {
+	for (i = 0; slot_suffix_arr[i] != NULL; i++) {
 		if (!strncmp(slot, slot_suffix_arr[i], strlen(slot_suffix_arr[i])))
 			slot_name_valid = 1;
 	}
@@ -176,10 +171,10 @@ static int update_slot_attribute(struct gpt_disk *disk, const char *slot,
 		return -1;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(ptn_list); i++) {
+	for (i = 0; i < ARRAY_SIZE(g_all_ptns); i++) {
 		memset(buf, '\0', sizeof(buf));
 		// Check if A/B versions of this ptn exist
-		snprintf(buf, sizeof(buf) - 1, "%s/%s%s", BOOT_DEV_DIR, ptn_list[i],
+		snprintf(buf, sizeof(buf) - 1, "%s/%s%s", BOOT_DEV_DIR, g_all_ptns[i],
 			 AB_SLOT_A_SUFFIX);
 		if (stat(buf, &st) < 0) {
 			// partition does not have _a version
@@ -187,7 +182,7 @@ static int update_slot_attribute(struct gpt_disk *disk, const char *slot,
 		}
 
 		memset(buf, '\0', sizeof(buf));
-		snprintf(buf, sizeof(buf) - 1, "%s/%s%s", BOOT_DEV_DIR, ptn_list[i],
+		snprintf(buf, sizeof(buf) - 1, "%s/%s%s", BOOT_DEV_DIR, g_all_ptns[i],
 			 AB_SLOT_B_SUFFIX);
 		if (stat(buf, &st) < 0) {
 			// partition does not have _b version
@@ -195,11 +190,11 @@ static int update_slot_attribute(struct gpt_disk *disk, const char *slot,
 		}
 
 		memset(partName, '\0', sizeof(partName));
-		snprintf(partName, sizeof(partName) - 1, "%s%s", ptn_list[i], slot);
+		snprintf(partName, sizeof(partName) - 1, "%s%s", g_all_ptns[i], slot);
 
 		// If the current partition is for a different disk (e.g. /dev/sde when the current disk is /dev/sda)
 		// Then commit the current disk
-		if (!partition_is_for_disk(partName, disk, devpath, sizeof(devpath))) {
+		if (partition_is_for_disk(disk, partName, devpath, sizeof(devpath)) != 0) {
 			if (!gpt_disk_commit(disk)) {
 				fprintf(stderr, "%s: Failed to commit disk\n", __func__);
 				return -1;
@@ -265,8 +260,8 @@ static int update_slot_attribute(struct gpt_disk *disk, const char *slot,
  */
 unsigned get_number_slots()
 {
-	struct dirent *de = nullptr;
-	DIR *dir_bootdev = nullptr;
+	struct dirent *de = NULL;
+	DIR *dir_bootdev = NULL;
 	static int slot_count = 0;
 
 	// If we've already counted the slots, return the cached value.
@@ -274,8 +269,8 @@ unsigned get_number_slots()
 	if (slot_count > 0)
 		return slot_count;
 
-	static_assert(AB_SLOT_A_SUFFIX[0] == '_', "Breaking change to slot A suffix");
-	static_assert(AB_SLOT_B_SUFFIX[0] == '_', "Breaking change to slot B suffix");
+	assert(AB_SLOT_A_SUFFIX[0] == '_');
+	assert(AB_SLOT_B_SUFFIX[0] == '_');
 
 	dir_bootdev = opendir(BOOTDEV_DIR);
 	// Shouldn't this be an assert?
@@ -344,7 +339,7 @@ static unsigned int get_current_slot_from_kernel_cmdline()
 
 	// Iterate through a list of partitons named as boot+suffix
 	// and see which one is currently active.
-	for (i = 0; slot_suffix_arr[i] != nullptr; i++) {
+	for (i = 0; slot_suffix_arr[i] != NULL; i++) {
 		if (!strncmp(bootSlotProp, slot_suffix_arr[i], strlen(slot_suffix_arr[i]))) {
 			// printf("%s current_slot = %d\n", __func__, i);
 			return i;
@@ -413,68 +408,66 @@ const char *get_suffix(unsigned slot)
 		return slot_suffix_arr[slot];
 }
 
+
 // The argument here is a vector of partition names(including the slot suffix)
 // that lie on a single disk
-static int boot_ctl_set_active_slot_for_partitions(struct gpt_disk *disk, vector<string> part_list,
+static int boot_ctl_set_active_slot_for_partitions(struct gpt_disk *disk, const char ptn_list[][MAX_GPT_NAME_SIZE], int len,
 						   unsigned slot)
 {
 	char buf[PATH_MAX] = { 0 };
-	char slotA[MAX_GPT_NAME_SIZE + 1] = { 0 };
-	char slotB[MAX_GPT_NAME_SIZE + 1] = { 0 };
+	const char *slotA;
+	char slotB[MAX_GPT_NAME_SIZE] = { 0 };
 	char active_guid[TYPE_GUID_SIZE + 1] = { 0 };
 	char inactive_guid[TYPE_GUID_SIZE + 1] = { 0 };
-	int rc;
+	int rc, i;
 	// Pointer to the partition entry of current 'A' partition
-	uint8_t *pentryA = nullptr;
-	uint8_t *pentryA_bak = nullptr;
+	uint8_t *pentryA = NULL;
+	uint8_t *pentryA_bak = NULL;
 	// Pointer to partition entry of current 'B' partition
-	uint8_t *pentryB = nullptr;
-	uint8_t *pentryB_bak = nullptr;
+	uint8_t *pentryB = NULL;
+	uint8_t *pentryB_bak = NULL;
 	struct stat st;
-	vector<string>::iterator partition_iterator;
 
 	LOGD("Marking slot %s as active:\n", slot_suffix_arr[slot]);
 
-	for (partition_iterator = part_list.begin(); partition_iterator != part_list.end();
-	     partition_iterator++) {
+	for (i = 0, slotA = ptn_list[0]; i < len; slotA = ptn_list[++i]) {
 		// Chop off the slot suffix from the partition name to
 		// make the string easier to work with.
-		string prefix = *partition_iterator;
-		LOGD("Part: %s\n", prefix.c_str());
-		if (prefix.size() < (strlen(AB_SLOT_A_SUFFIX) + 1)) {
-			fprintf(stderr, "Invalid partition name: %s\n", prefix.c_str());
+		LOGD("Part: %s\n", slotA);
+		int n = strlen(slotA) - strlen(AB_SLOT_A_SUFFIX);
+		if (n + 1 < 3 || n + 1 > MAX_GPT_NAME_SIZE) {
+			fprintf(stderr, "Invalid partition name: %s\n", slotA);
 			return -1;
 		}
-		prefix.resize(prefix.size() - strlen(AB_SLOT_A_SUFFIX));
-		// Check if A/B versions of this ptn exist
-		snprintf(buf, sizeof(buf) - 1, "%s/%s%s", BOOT_DEV_DIR, prefix.c_str(),
-			 AB_SLOT_A_SUFFIX);
-		LOGD("\t_a Path: '%s'\n", buf);
-		rc = stat(buf, &st);
-		if (rc < 0) {
-			fprintf(stderr, "Failed to stat() path: %d: %s\n", rc, strerror(errno));
-			continue;
-		}
-		memset(buf, '\0', sizeof(buf));
-		snprintf(buf, sizeof(buf) - 1, "%s/%s%s", BOOT_DEV_DIR, prefix.c_str(),
-			 AB_SLOT_B_SUFFIX);
-		// LOGD("\t_b Path: '%s'\n", buf);
-		rc = stat(buf, &st);
-		if (rc < 0) {
-			fprintf(stderr, "Failed to stat() path: %d: %s\n", rc, strerror(errno));
+
+		memset(slotB, 0, sizeof(slotB));
+		strncat(slotB, slotA, n);
+		strncat(slotB + n, AB_SLOT_B_SUFFIX, 3);
+
+		rc = snprintf(buf, sizeof(buf) - 1, "%s", BOOT_DEV_DIR);
+		snprintf(buf + rc, PATH_MAX - rc, "/%s", slotA);
+		LOGD("Checking for partition %s\n", buf);
+		if (stat(buf, &st)) {
+			if (!strcmp(slotA, "boot_a") || !strcmp(slotA, "dtbo_a")) {
+				fprintf(stderr, "Couldn't find required partition %s\n", slotA);
+				return -1;
+			}
+			// Not every device has every partition
 			continue;
 		}
-		memset(slotA, 0, sizeof(slotA));
-		memset(slotB, 0, sizeof(slotA));
-		snprintf(slotA, sizeof(slotA) - 1, "%s%s", prefix.c_str(), AB_SLOT_A_SUFFIX);
-		snprintf(slotB, sizeof(slotB) - 1, "%s%s", prefix.c_str(), AB_SLOT_B_SUFFIX);
-
-		// Get the disk containing the partitions that were passed in.
-		// All partitions passed in must lie on the same disk.
-		if (!gpt_disk_is_valid(disk)) {
-			if (gpt_disk_get_disk_info(slotA, disk) < 0)
-				return -1;
+
+		snprintf(buf + rc, PATH_MAX - rc, "/%s", slotB);
+		if (stat(buf, &st)) {
+			fprintf(stderr, "Partition %s does not exist\n", slotB);
+			return -1;
 		}
+
+		// Get the disk containing this partition. This only
+		// actually re-initialises disk if this partition refers
+		// to a different block device than the last one.
+		if (gpt_disk_get_disk_info(slotA, disk) < 0)
+			return -1;
+
 		// Get partition entry for slot A & B from the primary
 		// and backup tables.
 		pentryA = gpt_disk_get_pentry(disk, slotA, PRIMARY_GPT);
@@ -484,7 +477,7 @@ static int boot_ctl_set_active_slot_for_partitions(struct gpt_disk *disk, vector
 		if (!pentryA || !pentryA_bak || !pentryB || !pentryB_bak) {
 			// None of these should be NULL since we have already
 			// checked for A & B versions earlier.
-			fprintf(stderr, "Slot pentries for %s not found.\n", prefix.c_str());
+			fprintf(stderr, "Slot pentries for %s not found.\n", slotA);
 			return -1;
 		}
 		LOGD("\tAB attr (A): 0x%x (backup: 0x%x)\n", *(uint16_t *)(pentryA + AB_FLAG_OFFSET),
@@ -558,86 +551,50 @@ unsigned get_active_boot_slot()
 
 int set_active_boot_slot(unsigned slot)
 {
-	map<string, vector<string>> ptn_map;
-	vector<string> ptn_vec;
-	const char ptn_list[][MAX_GPT_NAME_SIZE] = { AB_PTN_LIST };
+	enum boot_chain chain = (enum boot_chain)slot;
 	struct gpt_disk disk = { 0 };
-	uint32_t i;
-	int rc = -1;
-	map<string, vector<string>>::iterator map_iter;
+	int rc;
 	bool ismmc;
 
 	if (boot_control_check_slot_sanity(slot)) {
 		fprintf(stderr, "%s: Bad arguments\n", __func__);
-		goto out;
+		return -1;
 	}
 
 	ismmc = gpt_utils_is_partition_backed_by_emmc(PTN_XBL AB_SLOT_A_SUFFIX);
 
+	// Do this *before* updating all the slot attributes
+	// to make sure we can
 	if (!ismmc && ufs_bsg_dev_open() < 0) {
-		goto out;
+		return -1;
 	}
 
-	// The partition list just contains prefixes(without the _a/_b) of the
-	// partitions that support A/B. In order to get the layout we need the
-	// actual names. To do this we append the slot suffix to every member
-	// in the list.
-	for (i = 0; i < ARRAY_SIZE(ptn_list); i++) {
-		// XBL is handled differrently for ufs devices so ignore it
-		if (!ismmc && !strncmp(ptn_list[i], PTN_XBL, strlen(PTN_XBL)))
-			continue;
-		// The partition list will be the list of _a partitions
-		string cur_ptn = ptn_list[i];
-		cur_ptn.append(AB_SLOT_A_SUFFIX);
-		ptn_vec.push_back(cur_ptn);
-	}
+	rc = boot_ctl_set_active_slot_for_partitions(&disk, g_all_ptns, ARRAY_SIZE(g_all_ptns), slot);
 
-	// The partition map gives us info in the following format:
-	// [path_to_block_device_1]--><partitions on device 1>
-	// [path_to_block_device_2]--><partitions on device 2>
-	// ...
-	// ...
-	// eg:
-	// [/dev/block/sdb]---><system, boot, rpm, tz,....>
-	if (gpt_utils_get_partition_map(ptn_vec, ptn_map)) {
-		fprintf(stderr, "%s: Failed to get partition map\n", __func__);
+	if (rc) {
+		fprintf(stderr, "%s: Failed to set active slot for partitions \n", __func__);
 		goto out;
 	}
-	for (map_iter = ptn_map.begin(); map_iter != ptn_map.end(); map_iter++) {
-		if (map_iter->second.size() < 1)
-			continue;
-		if (boot_ctl_set_active_slot_for_partitions(&disk, map_iter->second, slot)) {
-			fprintf(stderr, "%s: Failed to set active slot for partitions \n", __func__);
-			goto out;
-		}
-	}
 
 	// EMMC doesn't need attributes to be set.
 	if (ismmc)
-		return 0;
+		goto out;
 
-	if (slot == 0) {
-		// Set xbl_a as the boot lun
-		rc = gpt_utils_set_xbl_boot_partition(NORMAL_BOOT);
-	} else if (slot == 1) {
-		// Set xbl_b as the boot lun
-		rc = gpt_utils_set_xbl_boot_partition(BACKUP_BOOT);
-	} else {
-		// Something has gone terribly terribly wrong
-		fprintf(stderr, "%s: Unknown slot suffix!\n", __func__);
+	if (chain > BACKUP_BOOT) {
+		fprintf(stderr, "%s: Unknown slot %d!\n", __func__, slot);
+		rc = -1;
 		goto out;
 	}
+
+	rc = gpt_utils_set_xbl_boot_partition(chain);
 	if (rc) {
 		fprintf(stderr, "%s: Failed to switch xbl boot partition\n", __func__);
 		goto out;
 	}
 
-	gpt_disk_free(&disk);
-	return 0;
-
 out:
 	gpt_disk_free(&disk);
-	return -1;
+	return rc;
 }
 
 int set_slot_as_unbootable(unsigned slot)
diff --git a/bootctrl_test.cpp b/bootctrl_test.c
similarity index 98%
rename from bootctrl_test.cpp
rename to bootctrl_test.c
index 284f5cf..bd3c6bb 100644
--- a/bootctrl_test.cpp
+++ b/bootctrl_test.c
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <stdbool.h>
 #include "bootctrl.h"
 
 struct test_state {
diff --git a/gpt-utils.cpp b/gpt-utils.c
similarity index 91%
rename from gpt-utils.cpp
rename to gpt-utils.c
index 59ce60f..38acc39 100644
--- a/gpt-utils.cpp
+++ b/gpt-utils.c
@@ -30,8 +30,10 @@
 
 #define _LARGEFILE64_SOURCE /* enable lseek64() */
 
-#include "assert.h"
+#include <assert.h>
 #include <asm/byteorder.h>
+#include <ctype.h>
+#include <stdlib.h>
 #include <dirent.h>
 #include <endian.h>
 #include <errno.h>
@@ -40,14 +42,11 @@
 #include <limits.h>
 #include <linux/fs.h>
 #include <linux/kernel.h>
-#include <map>
 #include <stdio.h>
 #include <string.h>
-#include <string>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <unistd.h>
-#include <vector>
 #include <zlib.h>
 
 #include "gpt-utils.h"
@@ -75,9 +74,6 @@
 #define LUN_NAME_START_LOC (sizeof("/dev/") - 1)
 #define BOOT_LUN_A_ID	   1
 #define BOOT_LUN_B_ID	   2
-/******************************************************************************
- * MACROS
- ******************************************************************************/
 
 #define GET_4_BYTES(ptr)                                                                           \
 	((uint32_t) * ((uint8_t *)(ptr)) | ((uint32_t) * ((uint8_t *)(ptr) + 1) << 8) |            \
@@ -97,10 +93,6 @@
 	*((uint8_t *)(ptr) + 2) = ((y) >> 16) & 0xff;                                              \
 	*((uint8_t *)(ptr) + 3) = ((y) >> 24) & 0xff;
 
-/******************************************************************************
- * TYPES
- ******************************************************************************/
-using namespace std;
 enum gpt_state { GPT_OK = 0, GPT_BAD_SIGNATURE, GPT_BAD_CRC };
 // List of LUN's containing boot critical images.
 // Required in the case of UFS devices
@@ -109,9 +101,6 @@ struct update_data {
 	uint32_t num_valid_entries;
 };
 
-/******************************************************************************
- * FUNCTIONS
- ******************************************************************************/
 void DumpHex(const void *data, size_t size)
 {
 	char ascii[17];
@@ -222,7 +211,7 @@ static uint8_t *gpt_pentry_seek(const char *ptn_name, const uint8_t *pentries_st
 				return (uint8_t *)(pentry_name - PARTITION_NAME_OFFSET);
 	}
 
-	return nullptr;
+	return NULL;
 }
 
 // Defined in ufs-bsg.cpp
@@ -249,7 +238,7 @@ int gpt_utils_set_xbl_boot_partition(enum boot_chain chain)
 {
 	struct stat st;
 	uint8_t boot_lun_id = 0;
-	const char *boot_dev = nullptr;
+	const char *boot_dev = NULL;
 
 	(void)st;
 	(void)boot_dev;
@@ -332,42 +321,6 @@ static int get_dev_path_from_partition_name(const char *partname, char *buf, siz
 	return 0;
 }
 
-int gpt_utils_get_partition_map(vector<string> &ptn_list, map<string, vector<string>> &partition_map)
-{
-	char devpath[PATH_MAX] = { '\0' };
-	map<string, vector<string>>::iterator it;
-
-	if (ptn_list.size() < 1) {
-		fprintf(stderr, "%s: Invalid ptn list\n", __func__);
-		return -1;
-	}
-
-	// Go through the passed in list
-	for (uint32_t i = 0; i < ptn_list.size(); i++) {
-		// Key in the map is the path to the device that holds the
-		// partition
-		if (get_dev_path_from_partition_name(ptn_list[i].c_str(), devpath, sizeof(devpath))) {
-			// Not necessarily an error. The partition may just
-			// not be present.
-			continue;
-		}
-
-		string path = devpath;
-		it = partition_map.find(path);
-		if (it != partition_map.end()) {
-			it->second.push_back(ptn_list[i]);
-		} else {
-			vector<string> str_vec;
-			str_vec.push_back(ptn_list[i]);
-			partition_map.insert(pair<string, vector<string>>(path, str_vec));
-		}
-	
-		memset(devpath, '\0', sizeof(devpath));
-	}
-
-	return 0;
-}
-
 // Get the block size of the disk represented by decsriptor fd
 static uint32_t gpt_get_block_size(int fd)
 {
@@ -432,7 +385,7 @@ error:
 // Read out the GPT headers for the disk that contains the partition partname
 static int gpt_get_headers(const char *partname, uint8_t **primary, uint8_t **backup)
 {
-	uint8_t *hdr = nullptr;
+	uint8_t *hdr = NULL;
 	char devpath[PATH_MAX] = { 0 };
 	off_t hdr_offset = 0;
 	uint32_t block_size = 0;
@@ -505,7 +458,7 @@ static uint8_t *gpt_get_pentry_arr(uint8_t *hdr, int fd)
 	uint32_t pentry_size = 0;
 	uint32_t block_size = 0;
 	uint32_t pentries_arr_size = 0;
-	uint8_t *pentry_arr = nullptr;
+	uint8_t *pentry_arr = NULL;
 	int rc = 0;
 	if (!hdr) {
 		fprintf(stderr, "%s: Invalid header\n", __func__);
@@ -537,7 +490,7 @@ static uint8_t *gpt_get_pentry_arr(uint8_t *hdr, int fd)
 error:
 	if (pentry_arr)
 		free(pentry_arr);
-	return nullptr;
+	return NULL;
 }
 
 static int gpt_set_pentry_arr(uint8_t *hdr, int fd, uint8_t *arr)
@@ -586,19 +539,19 @@ void gpt_disk_free(struct gpt_disk *disk)
 
 	if (disk->hdr) {
 		free(disk->hdr);
-		disk->hdr = nullptr;
+		disk->hdr = NULL;
 	}
 	if (disk->hdr_bak) {
 		free(disk->hdr_bak);
-		disk->hdr_bak = nullptr;
+		disk->hdr_bak = NULL;
 	}
 	if (disk->pentry_arr) {
 		free(disk->pentry_arr);
-		disk->pentry_arr = nullptr;
+		disk->pentry_arr = NULL;
 	}
 	if (disk->pentry_arr_bak) {
 		free(disk->pentry_arr_bak);
-		disk->pentry_arr_bak = nullptr;
+		disk->pentry_arr_bak = NULL;
 	}
 
 	disk->is_initialized = 0;
@@ -616,14 +569,14 @@ bool gpt_disk_is_valid(struct gpt_disk *disk)
  * and populate the blockdev path.
  * e.g. for /dev/disk/by-partlabel/system_a blockdev would be /dev/sda
  */
-bool partition_is_for_disk(const char *part, struct gpt_disk *disk, char *blockdev, int blockdev_len)
+int partition_is_for_disk(const struct gpt_disk *disk, const char *part, char *blockdev, int blockdev_len)
 {
 	int ret;
 
 	ret = get_dev_path_from_partition_name(part, blockdev, blockdev_len);
 	if (ret) {
 		fprintf(stderr, "%s: Failed to resolve path for %s\n", __func__, part);
-		return false;
+		return -1;
 	}
 
 	if (!strcmp(blockdev, disk->devpath)) {
@@ -639,7 +592,7 @@ bool partition_is_for_disk(const char *part, struct gpt_disk *disk, char *blockd
  */
 int gpt_disk_get_disk_info(const char *dev, struct gpt_disk *disk)
 {
-	int fd = -1;
+	int fd = -1, rc;
 	uint32_t gpt_header_size = 0;
 	char devpath[PATH_MAX] = { 0 };
 
@@ -648,8 +601,14 @@ int gpt_disk_get_disk_info(const char *dev, struct gpt_disk *disk)
 		goto error;
 	}
 
-	if (partition_is_for_disk(dev, disk, devpath, sizeof(devpath))) {
+	rc = partition_is_for_disk(disk, dev, devpath, sizeof(devpath));
+
+	if (rc > 0)
 		return 0;
+
+	if (rc < 0) {
+		fprintf(stderr, "%s: Failed to resolve path for %s\n", __func__, dev);
+		return -1;
 	}
 
 	if (disk->is_initialized == GPT_DISK_INIT_MAGIC) {
@@ -666,8 +625,8 @@ int gpt_disk_get_disk_info(const char *dev, struct gpt_disk *disk)
 		goto error;
 	}
 
-	assert(disk->hdr != nullptr);
-	assert(disk->hdr_bak != nullptr);
+	assert(disk->hdr != NULL);
+	assert(disk->hdr_bak != NULL);
 
 	gpt_header_size = GET_4_BYTES(disk->hdr + HEADER_SIZE_OFFSET);
 
@@ -683,14 +642,14 @@ int gpt_disk_get_disk_info(const char *dev, struct gpt_disk *disk)
 		goto error;
 	}
 
-	assert(disk->pentry_arr == nullptr);
+	assert(disk->pentry_arr == NULL);
 	disk->pentry_arr = gpt_get_pentry_arr(disk->hdr, fd);
 	if (!disk->pentry_arr) {
 		fprintf(stderr, "%s: Failed to obtain partition entry array\n", __func__);
 		goto error;
 	}
 
-	assert(disk->pentry_arr_bak == nullptr);
+	assert(disk->pentry_arr_bak == NULL);
 	disk->pentry_arr_bak = gpt_get_pentry_arr(disk->hdr_bak, fd);
 	if (!disk->pentry_arr_bak) {
 		fprintf(stderr, "%s: Failed to obtain backup partition entry array\n", __func__);
@@ -714,10 +673,10 @@ error:
 // Get pointer to partition entry from a allocated gpt_disk structure
 uint8_t *gpt_disk_get_pentry(struct gpt_disk *disk, const char *partname, enum gpt_instance instance)
 {
-	uint8_t *ptn_arr = nullptr;
+	uint8_t *ptn_arr = NULL;
 	if (!disk || !partname || disk->is_initialized != GPT_DISK_INIT_MAGIC) {
 		fprintf(stderr, "%s: disk handle not initialised\n", __func__);
-		return nullptr;
+		return NULL;
 	}
 	ptn_arr = (instance == PRIMARY_GPT) ? disk->pentry_arr : disk->pentry_arr_bak;
 	return (gpt_pentry_seek(partname, ptn_arr, ptn_arr + disk->pentry_arr_size,
diff --git a/gpt-utils.h b/gpt-utils.h
index a4eb9e4..4379189 100644
--- a/gpt-utils.h
+++ b/gpt-utils.h
@@ -29,13 +29,11 @@
 
 #ifndef __GPT_UTILS_H__
 #define __GPT_UTILS_H__
-#include <vector>
-#include <string>
-#include <map>
 #ifdef __cplusplus
 extern "C" {
 #endif
 #include <unistd.h>
+#include <stdbool.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <linux/limits.h>
@@ -62,8 +60,8 @@ extern "C" {
 #define PARTITION_NAME_OFFSET	56
 #define MAX_GPT_NAME_SIZE	72
 
-//Bit 48 onwords in the attribute field are the ones where we are allowed to
-//store our AB attributes.
+// Bit 48 onwords in the attribute field are the ones where we are allowed to
+// store our AB attributes.
 #define AB_FLAG_OFFSET			  (ATTRIBUTE_FLAG_OFFSET + 6)
 #define GPT_DISK_INIT_MAGIC		  0xABCD
 #define AB_PARTITION_ATTR_SLOT_ACTIVE	  (0x1 << 2)
@@ -76,14 +74,22 @@ extern "C" {
 #define AB_SLOT_A_SUFFIX		  "_a"
 #define AB_SLOT_B_SUFFIX		  "_b"
 #define PTN_XBL				  "xbl"
-#define PTN_SWAP_LIST                                                          \
-	PTN_XBL, "abl", "aop", "apdp", "cmnlib", "cmnlib64", "devcfg", "dtbo", \
-		"hyp", "keymaster", "msadp", "qupfw", "storsec", "tz",         \
-		"vbmeta", "vbmeta_system", "xbl_config"
-
-#define AB_PTN_LIST                                                            \
-	PTN_SWAP_LIST, "boot", "system", "vendor", "modem", "system_ext",      \
-		"product"
+// XBL is not included because the slot attributes are meaningless there
+// *which* XBL partition is active is determined via the UFS bBootLunEn field
+// as it needs to be handled by PBL
+#define PTN_SWAP_LIST \
+	"abl_a", "aop_a", "apdp_a", "cmnlib_a", "cmnlib64_a", "devcfg_a", "dtbo_a", \
+	"hyp_a", "keymaster_a", "msadp_a", "qupfw_a", "storsec_a", "tz_a", \
+	"vbmeta_a", "vbmeta_system_a"
+
+static const char g_all_ptns[][MAX_GPT_NAME_SIZE] = {
+	PTN_SWAP_LIST, "boot_a", "system",
+	"vendor_a", "modem_a", "system_ext_a", "product_a"
+};
+
+// No more than /dev/sdk
+#define MAX_BLOCK_DEVICES 10
+
 #define BOOT_DEV_DIR  "/dev/disk/by-partlabel"
 
 #define EMMC_DEVICE "/dev/mmcblk0"
@@ -95,78 +101,69 @@ enum gpt_instance { PRIMARY_GPT = 0, SECONDARY_GPT };
 enum boot_chain { NORMAL_BOOT = 0, BACKUP_BOOT };
 
 struct gpt_disk {
-	//GPT primary header
+	// GPT primary header
 	uint8_t *hdr;
-	//primary header crc
+	// primary header crc
 	uint32_t hdr_crc;
-	//GPT backup header
+	// GPT backup header
 	uint8_t *hdr_bak;
-	//backup header crc
+	// backup header crc
 	uint32_t hdr_bak_crc;
-	//Partition entries array
+	// Partition entries array
 	uint8_t *pentry_arr;
-	//Partition entries array for backup table
+	// Partition entries array for backup table
 	uint8_t *pentry_arr_bak;
-	//Size of the pentry array
+	// Size of the pentry array
 	uint32_t pentry_arr_size;
-	//Size of each element in the pentry array
+	// Size of each element in the pentry array
 	uint32_t pentry_size;
-	//CRC of the partition entry array
+	// CRC of the partition entry array
 	uint32_t pentry_arr_crc;
-	//CRC of the backup partition entry array
+	// CRC of the backup partition entry array
 	uint32_t pentry_arr_bak_crc;
-	//Path to block dev representing the disk
+	// Path to block dev representing the disk
 	char devpath[PATH_MAX];
-	//Block size of disk
+	// Block size of disk
 	uint32_t block_size;
 	uint32_t is_initialized;
 };
 
-//GPT disk methods
+// GPT disk methods
 bool gpt_disk_is_valid(struct gpt_disk *disk);
-//Free previously allocated gpt_disk struct
+// Free previously allocated gpt_disk struct
 void gpt_disk_free(struct gpt_disk *disk);
-//Get the details of the disk holding the partition whose name
-//is passed in via dev
+// Get the details of the disk holding the partition whose name
+// is passed in via dev
 int gpt_disk_get_disk_info(const char *dev, struct gpt_disk *disk);
 
-bool partition_is_for_disk(const char *part, struct gpt_disk *disk, char *blockdev, int blockdev_len);
+int partition_is_for_disk(const struct gpt_disk *disk, const char *part, char *blockdev, int blockdev_len);
 
-//Get pointer to partition entry from a allocated gpt_disk structure
+// Get pointer to partition entry from a allocated gpt_disk structure
 uint8_t *gpt_disk_get_pentry(struct gpt_disk *disk, const char *partname,
 			     enum gpt_instance instance);
 
-//Write the contents of struct gpt_disk back to the actual disk
+// Write the contents of struct gpt_disk back to the actual disk
 int gpt_disk_commit(struct gpt_disk *disk);
 
-//Swtich betwieen using either the primary or the backup
-//boot LUN for boot. This is required since UFS boot partitions
-//cannot have a backup GPT which is what we use for failsafe
-//updates of the other 'critical' partitions. This function will
-//not be invoked for emmc targets and on UFS targets is only required
-//to be invoked for XBL.
+// Swtich betwieen using either the primary or the backup
+// boot LUN for boot. This is required since UFS boot partitions
+// cannot have a backup GPT which is what we use for failsafe
+// updates of the other 'critical' partitions. This function will
+// not be invoked for emmc targets and on UFS targets is only required
+// to be invoked for XBL.
 //
-//The algorithm to do this is as follows:
-//- Find the real block device(eg: /dev/block/sdb) that corresponds
+// The algorithm to do this is as follows:
+// - Find the real block device(eg: /dev/block/sdb) that corresponds
 //  to the /dev/block/bootdevice/by-name/xbl(bak) symlink
 //
-//- Once we have the block device 'node' name(sdb in the above example)
+// - Once we have the block device 'node' name(sdb in the above example)
 //  use this node to to locate the scsi generic device that represents
 //  it by checking the file /sys/block/sdb/device/scsi_generic/sgY
 //
-//- Once we locate sgY we call the query ioctl on /dev/sgy to switch
-//the boot lun to either LUNA or LUNB
+// - Once we locate sgY we call the query ioctl on /dev/sgy to switch
+// the boot lun to either LUNA or LUNB
 int gpt_utils_set_xbl_boot_partition(enum boot_chain chain);
 
-//Given a vector of partition names as a input and a reference to a map,
-//populate the map to indicate which physical disk each of the partitions
-//sits on. The key in the map is the path to the block device where the
-//partition lies and the value is a vector of strings indicating which of
-//the passed in partition names sits on that device.
-int gpt_utils_get_partition_map(
-	std::vector<std::string> &partition_list,
-	std::map<std::string, std::vector<std::string> > &partition_map);
-
 bool gpt_utils_is_partition_backed_by_emmc(const char *part);
 #ifdef __cplusplus
 }
diff --git a/meson.build b/meson.build
index afe7d3c..d112c64 100644
--- a/meson.build
+++ b/meson.build
@@ -1,6 +1,6 @@
-project('qbootctl', 'cpp', default_options : ['c_std=c11', 'cpp_std=c++17'])
+project('qbootctl', 'c', default_options : ['c_std=c11'])
 
-cc = meson.get_compiler('cpp')
+cc = meson.get_compiler('c')
 
 deps = [
         dependency('zlib'),
@@ -11,11 +11,11 @@ if not cc.has_header('linux/bsg.h')
 endif
 
 src = [
-        'qbootctl.cpp',
-        'bootctrl_impl.cpp',
-        'bootctrl_test.cpp',
-        'gpt-utils.cpp',
-        'ufs-bsg.cpp',
+        'qbootctl.c',
+        'bootctrl_impl.c',
+        'bootctrl_test.c',
+        'gpt-utils.c',
+        'ufs-bsg.c',
 ]
 
 inc = [
diff --git a/qbootctl.cpp b/qbootctl.c
similarity index 99%
rename from qbootctl.cpp
rename to qbootctl.c
index a666b82..4936b9e 100644
--- a/qbootctl.cpp
+++ b/qbootctl.c
@@ -20,6 +20,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <stdbool.h>
 #include <stdint.h>
 
 #include "bootctrl.h"
diff --git a/ufs-bsg.cpp b/ufs-bsg.c
similarity index 93%
rename from ufs-bsg.cpp
rename to ufs-bsg.c
index 8b66342..05c8885 100644
--- a/ufs-bsg.cpp
+++ b/ufs-bsg.c
@@ -81,16 +81,16 @@ static int ufs_bsg_ioctl(int fd, struct ufs_bsg_request *req,
 			 enum bsg_ioctl_dir dir)
 {
 	int ret;
-	struct sg_io_v4 sg_io {
+	struct sg_io_v4 sg_io = {
+		.guard = 'Q',
+		.protocol = BSG_PROTOCOL_SCSI,
+		.subprotocol = BSG_SUB_PROTOCOL_SCSI_TRANSPORT,
+		.request_len = sizeof(*req),
+		.request = (__u64)req,
+		.response = (__u64)rsp,
+		.max_response_len = sizeof(*rsp),
 	};
 
-	sg_io.guard = 'Q';
-	sg_io.protocol = BSG_PROTOCOL_SCSI;
-	sg_io.subprotocol = BSG_SUB_PROTOCOL_SCSI_TRANSPORT;
-	sg_io.request_len = sizeof(*req);
-	sg_io.request = (__u64)req;
-	sg_io.response = (__u64)rsp;
-	sg_io.max_response_len = sizeof(*rsp);
 	if (dir == BSG_IOCTL_DIR_FROM_DEV) {
 		sg_io.din_xfer_len = buf_len;
 		sg_io.din_xferp = (__u64)(buf);
@@ -137,10 +137,8 @@ static void compose_ufs_bsg_query_req(struct ufs_bsg_request *req, __u8 func,
 static int ufs_query_attr(int fd, __u32 value, __u8 func, __u8 opcode, __u8 idn,
 			  __u8 index, __u8 sel)
 {
-	struct ufs_bsg_request req {
-	};
-	struct ufs_bsg_reply rsp {
-	};
+	struct ufs_bsg_request req = { 0 };
+	struct ufs_bsg_reply rsp = { 0 };
 	enum bsg_ioctl_dir dir = BSG_IOCTL_DIR_FROM_DEV;
 	int ret = 0;