Merge tag 'u-boot-dfu-20240215' of https://source.denx.de/u-boot/custodians/u-boot-dfuWIP/15Feb2024

u-boot-dfu-20240215

- Fix avb_verify command with SD cards
- Add u-boot-dfu maintainer tree for AB/AVB
- Avb: report verified boot state based on lock state
- Misc avb refactors improve code quality

6 files changed, 180 insertions, 110 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 46ba176..32f3ee3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -62,6 +62,7 @@ M:	Igor Opaniuk <igor.opaniuk@gmail.com>
 M:	Mattijs Korpershoek <mkorpershoek@baylibre.com>
 R:	Sam Protsenko <semen.protsenko@linaro.org>
 S:	Maintained
+T:	git https://source.denx.de/u-boot/custodians/u-boot-dfu.git
 F:	boot/android_ab.c
 F:	cmd/ab_select.c
 F:	doc/android/ab.rst
@@ -72,6 +73,7 @@ ANDROID AVB
 M:	Igor Opaniuk <igor.opaniuk@gmail.com>
 M:	Mattijs Korpershoek <mkorpershoek@baylibre.com>
 S:	Maintained
+T:	git https://source.denx.de/u-boot/custodians/u-boot-dfu.git
 F:	cmd/avb.c
 F:	common/avb_verify.c
 F:	doc/android/avb2.rst
diff --git a/cmd/avb.c b/cmd/avb.c
index 783f51b..8fbd48e 100644
--- a/cmd/avb.c
+++ b/cmd/avb.c
@@ -1,8 +1,6 @@
-
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2018, Linaro Limited
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <avb_verify.h>
@@ -13,6 +11,7 @@
 #include <mmc.h>
 
 #define AVB_BOOTARGS	"avb_bootargs"
+
 static struct AvbOps *avb_ops;
 
 int do_avb_init(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
@@ -30,8 +29,10 @@ int do_avb_init(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	avb_ops = avb_ops_alloc(mmc_dev);
 	if (avb_ops)
 		return CMD_RET_SUCCESS;
+	else
+		printf("Can't allocate AvbOps");
 
-	printf("Failed to initialize avb2\n");
+	printf("Failed to initialize AVB\n");
 
 	return CMD_RET_FAILURE;
 }
@@ -43,10 +44,11 @@ int do_avb_read_part(struct cmd_tbl *cmdtp, int flag, int argc,
 	s64 offset;
 	size_t bytes, bytes_read = 0;
 	void *buffer;
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, please run 'avb init'\n");
-		return CMD_RET_USAGE;
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
+		return CMD_RET_FAILURE;
 	}
 
 	if (argc != 5)
@@ -57,14 +59,15 @@ int do_avb_read_part(struct cmd_tbl *cmdtp, int flag, int argc,
 	bytes = hextoul(argv[3], NULL);
 	buffer = (void *)hextoul(argv[4], NULL);
 
-	if (avb_ops->read_from_partition(avb_ops, part, offset, bytes,
-					 buffer, &bytes_read) ==
-					 AVB_IO_RESULT_OK) {
+	ret = avb_ops->read_from_partition(avb_ops, part, offset,
+					   bytes, buffer, &bytes_read);
+	if (ret == AVB_IO_RESULT_OK) {
 		printf("Read %zu bytes\n", bytes_read);
 		return CMD_RET_SUCCESS;
 	}
 
-	printf("Failed to read from partition\n");
+	printf("Failed to read from partition '%s', err = %d\n",
+	       part, ret);
 
 	return CMD_RET_FAILURE;
 }
@@ -76,10 +79,11 @@ int do_avb_read_part_hex(struct cmd_tbl *cmdtp, int flag, int argc,
 	s64 offset;
 	size_t bytes, bytes_read = 0;
 	char *buffer;
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, please run 'avb init'\n");
-		return CMD_RET_USAGE;
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
+		return CMD_RET_FAILURE;
 	}
 
 	if (argc != 4)
@@ -96,8 +100,9 @@ int do_avb_read_part_hex(struct cmd_tbl *cmdtp, int flag, int argc,
 	}
 	memset(buffer, 0, bytes);
 
-	if (avb_ops->read_from_partition(avb_ops, part, offset, bytes, buffer,
-					 &bytes_read) == AVB_IO_RESULT_OK) {
+	ret = avb_ops->read_from_partition(avb_ops, part, offset,
+					   bytes, buffer, &bytes_read);
+	if (ret == AVB_IO_RESULT_OK) {
 		printf("Requested %zu, read %zu bytes\n", bytes, bytes_read);
 		printf("Data: ");
 		for (int i = 0; i < bytes_read; i++)
@@ -109,7 +114,8 @@ int do_avb_read_part_hex(struct cmd_tbl *cmdtp, int flag, int argc,
 		return CMD_RET_SUCCESS;
 	}
 
-	printf("Failed to read from partition\n");
+	printf("Failed to read from partition '%s', err = %d\n",
+	       part, ret);
 
 	free(buffer);
 	return CMD_RET_FAILURE;
@@ -122,9 +128,10 @@ int do_avb_write_part(struct cmd_tbl *cmdtp, int flag, int argc,
 	s64 offset;
 	size_t bytes;
 	void *buffer;
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
 		return CMD_RET_FAILURE;
 	}
 
@@ -136,13 +143,15 @@ int do_avb_write_part(struct cmd_tbl *cmdtp, int flag, int argc,
 	bytes = hextoul(argv[3], NULL);
 	buffer = (void *)hextoul(argv[4], NULL);
 
-	if (avb_ops->write_to_partition(avb_ops, part, offset, bytes, buffer) ==
-	    AVB_IO_RESULT_OK) {
+	ret = avb_ops->write_to_partition(avb_ops, part, offset,
+					  bytes, buffer);
+	if (ret == AVB_IO_RESULT_OK) {
 		printf("Wrote %zu bytes\n", bytes);
 		return CMD_RET_SUCCESS;
 	}
 
-	printf("Failed to write in partition\n");
+	printf("Failed to write in partition '%s', err = %d\n",
+	       part, ret);
 
 	return CMD_RET_FAILURE;
 }
@@ -152,9 +161,10 @@ int do_avb_read_rb(struct cmd_tbl *cmdtp, int flag, int argc,
 {
 	size_t index;
 	u64 rb_idx;
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
 		return CMD_RET_FAILURE;
 	}
 
@@ -163,13 +173,14 @@ int do_avb_read_rb(struct cmd_tbl *cmdtp, int flag, int argc,
 
 	index = (size_t)hextoul(argv[1], NULL);
 
-	if (avb_ops->read_rollback_index(avb_ops, index, &rb_idx) ==
-	    AVB_IO_RESULT_OK) {
+	ret = avb_ops->read_rollback_index(avb_ops, index, &rb_idx);
+	if (ret == AVB_IO_RESULT_OK) {
 		printf("Rollback index: %llx\n", rb_idx);
 		return CMD_RET_SUCCESS;
 	}
 
-	printf("Failed to read rollback index\n");
+	printf("Failed to read rollback index id = %zu, err = %d\n",
+	       index, ret);
 
 	return CMD_RET_FAILURE;
 }
@@ -179,9 +190,10 @@ int do_avb_write_rb(struct cmd_tbl *cmdtp, int flag, int argc,
 {
 	size_t index;
 	u64 rb_idx;
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
 		return CMD_RET_FAILURE;
 	}
 
@@ -191,11 +203,12 @@ int do_avb_write_rb(struct cmd_tbl *cmdtp, int flag, int argc,
 	index = (size_t)hextoul(argv[1], NULL);
 	rb_idx = hextoul(argv[2], NULL);
 
-	if (avb_ops->write_rollback_index(avb_ops, index, rb_idx) ==
-	    AVB_IO_RESULT_OK)
+	ret = avb_ops->write_rollback_index(avb_ops, index, rb_idx);
+	if (ret == AVB_IO_RESULT_OK)
 		return CMD_RET_SUCCESS;
 
-	printf("Failed to write rollback index\n");
+	printf("Failed to write rollback index id = %zu, err = %d\n",
+	       index, ret);
 
 	return CMD_RET_FAILURE;
 }
@@ -205,9 +218,10 @@ int do_avb_get_uuid(struct cmd_tbl *cmdtp, int flag,
 {
 	const char *part;
 	char buffer[UUID_STR_LEN + 1];
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
 		return CMD_RET_FAILURE;
 	}
 
@@ -216,14 +230,16 @@ int do_avb_get_uuid(struct cmd_tbl *cmdtp, int flag,
 
 	part = argv[1];
 
-	if (avb_ops->get_unique_guid_for_partition(avb_ops, part, buffer,
-						   UUID_STR_LEN + 1) ==
-						   AVB_IO_RESULT_OK) {
+	ret = avb_ops->get_unique_guid_for_partition(avb_ops, part,
+						     buffer,
+						     UUID_STR_LEN + 1);
+	if (ret == AVB_IO_RESULT_OK) {
 		printf("'%s' UUID: %s\n", part, buffer);
 		return CMD_RET_SUCCESS;
 	}
 
-	printf("Failed to read UUID\n");
+	printf("Failed to read partition '%s' UUID, err = %d\n",
+	       part, ret);
 
 	return CMD_RET_FAILURE;
 }
@@ -234,15 +250,17 @@ int do_avb_verify_part(struct cmd_tbl *cmdtp, int flag,
 	const char * const requested_partitions[] = {"boot", NULL};
 	AvbSlotVerifyResult slot_result;
 	AvbSlotVerifyData *out_data;
+	enum avb_boot_state boot_state;
 	char *cmdline;
 	char *extra_args;
 	char *slot_suffix = "";
+	int ret;
 
 	bool unlocked = false;
 	int res = CMD_RET_FAILURE;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
 		return CMD_RET_FAILURE;
 	}
 
@@ -255,9 +273,10 @@ int do_avb_verify_part(struct cmd_tbl *cmdtp, int flag,
 	printf("## Android Verified Boot 2.0 version %s\n",
 	       avb_version_string());
 
-	if (avb_ops->read_is_device_unlocked(avb_ops, &unlocked) !=
-	    AVB_IO_RESULT_OK) {
-		printf("Can't determine device lock state.\n");
+	ret = avb_ops->read_is_device_unlocked(avb_ops, &unlocked);
+	if (ret != AVB_IO_RESULT_OK) {
+		printf("Can't determine device lock state, err = %d\n",
+		       ret);
 		return CMD_RET_FAILURE;
 	}
 
@@ -269,18 +288,23 @@ int do_avb_verify_part(struct cmd_tbl *cmdtp, int flag,
 				AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE,
 				&out_data);
 
-	switch (slot_result) {
-	case AVB_SLOT_VERIFY_RESULT_OK:
-		/* Until we don't have support of changing unlock states, we
-		 * assume that we are by default in locked state.
-		 * So in this case we can boot only when verification is
-		 * successful; we also supply in cmdline GREEN boot state
-		 */
+	/*
+	 * LOCKED devices with custom root of trust setup is not supported (YELLOW)
+	 */
+	if (slot_result == AVB_SLOT_VERIFY_RESULT_OK) {
 		printf("Verification passed successfully\n");
 
-		/* export additional bootargs to AVB_BOOTARGS env var */
+		/*
+		 * ORANGE state indicates that device may be freely modified.
+		 * Device integrity is left to the user to verify out-of-band.
+		 */
+		if (unlocked)
+			boot_state = AVB_ORANGE;
+		else
+			boot_state = AVB_GREEN;
 
-		extra_args = avb_set_state(avb_ops, AVB_GREEN);
+		/* export boot state to AVB_BOOTARGS env var */
+		extra_args = avb_set_state(avb_ops, boot_state);
 		if (extra_args)
 			cmdline = append_cmd_line(out_data->cmdline,
 						  extra_args);
@@ -290,30 +314,8 @@ int do_avb_verify_part(struct cmd_tbl *cmdtp, int flag,
 		env_set(AVB_BOOTARGS, cmdline);
 
 		res = CMD_RET_SUCCESS;
-		break;
-	case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
-		printf("Verification failed\n");
-		break;
-	case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
-		printf("I/O error occurred during verification\n");
-		break;
-	case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
-		printf("OOM error occurred during verification\n");
-		break;
-	case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
-		printf("Corrupted dm-verity metadata detected\n");
-		break;
-	case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
-		printf("Unsupported version avbtool was used\n");
-		break;
-	case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
-		printf("Checking rollback index failed\n");
-		break;
-	case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
-		printf("Public key was rejected\n");
-		break;
-	default:
-		printf("Unknown error occurred\n");
+	} else {
+		printf("Verification failed, reason: %s\n", str_avb_slot_error(slot_result));
 	}
 
 	if (out_data)
@@ -326,9 +328,10 @@ int do_avb_is_unlocked(struct cmd_tbl *cmdtp, int flag,
 		       int argc, char *const argv[])
 {
 	bool unlock;
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB not initialized, run 'avb init' first\n");
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
 		return CMD_RET_FAILURE;
 	}
 
@@ -337,13 +340,14 @@ int do_avb_is_unlocked(struct cmd_tbl *cmdtp, int flag,
 		return CMD_RET_USAGE;
 	}
 
-	if (avb_ops->read_is_device_unlocked(avb_ops, &unlock) ==
-	    AVB_IO_RESULT_OK) {
+	ret = avb_ops->read_is_device_unlocked(avb_ops, &unlock);
+	if (ret == AVB_IO_RESULT_OK) {
 		printf("Unlocked = %d\n", unlock);
 		return CMD_RET_SUCCESS;
 	}
 
-	printf("Can't determine device lock state.\n");
+	printf("Can't determine device lock state, err = %d\n",
+	       ret);
 
 	return CMD_RET_FAILURE;
 }
@@ -356,9 +360,10 @@ int do_avb_read_pvalue(struct cmd_tbl *cmdtp, int flag, int argc,
 	size_t bytes_read;
 	void *buffer;
 	char *endp;
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
 		return CMD_RET_FAILURE;
 	}
 
@@ -374,15 +379,16 @@ int do_avb_read_pvalue(struct cmd_tbl *cmdtp, int flag, int argc,
 	if (!buffer)
 		return CMD_RET_FAILURE;
 
-	if (avb_ops->read_persistent_value(avb_ops, name, bytes, buffer,
-					   &bytes_read) == AVB_IO_RESULT_OK) {
+	ret = avb_ops->read_persistent_value(avb_ops, name, bytes,
+					     buffer, &bytes_read);
+	if (ret == AVB_IO_RESULT_OK) {
 		printf("Read %zu bytes, value = %s\n", bytes_read,
 		       (char *)buffer);
 		free(buffer);
 		return CMD_RET_SUCCESS;
 	}
 
-	printf("Failed to read persistent value\n");
+	printf("Failed to read persistent value, err = %d\n", ret);
 
 	free(buffer);
 
@@ -394,9 +400,10 @@ int do_avb_write_pvalue(struct cmd_tbl *cmdtp, int flag, int argc,
 {
 	const char *name;
 	const char *value;
+	int ret;
 
 	if (!avb_ops) {
-		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		printf("AVB is not initialized, please run 'avb init <id>'\n");
 		return CMD_RET_FAILURE;
 	}
 
@@ -406,14 +413,16 @@ int do_avb_write_pvalue(struct cmd_tbl *cmdtp, int flag, int argc,
 	name = argv[1];
 	value = argv[2];
 
-	if (avb_ops->write_persistent_value(avb_ops, name, strlen(value) + 1,
-					    (const uint8_t *)value) ==
-	    AVB_IO_RESULT_OK) {
+	ret = avb_ops->write_persistent_value(avb_ops, name,
+					      strlen(value) + 1,
+					      (const uint8_t *)value);
+	if (ret == AVB_IO_RESULT_OK) {
 		printf("Wrote %zu bytes\n", strlen(value) + 1);
 		return CMD_RET_SUCCESS;
 	}
 
-	printf("Failed to write persistent value\n");
+	printf("Failed to write persistent value `%s` = `%s`, err = %d\n",
+	       name, value, ret);
 
 	return CMD_RET_FAILURE;
 }
diff --git a/common/avb_verify.c b/common/avb_verify.c
index 48ba8db..cff9117 100644
--- a/common/avb_verify.c
+++ b/common/avb_verify.c
@@ -1,7 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2018, Linaro Limited
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <avb_verify.h>
@@ -120,6 +119,55 @@ static const unsigned char avb_root_pub[1032] = {
 	0xd8, 0x7e,
 };
 
+const char *str_avb_io_error(AvbIOResult res)
+{
+	switch (res) {
+	case AVB_IO_RESULT_OK:
+		return "Requested operation was successful";
+	case AVB_IO_RESULT_ERROR_IO:
+		return "Underlying hardware encountered an I/O error";
+	case AVB_IO_RESULT_ERROR_OOM:
+		return "Unable to allocate memory";
+	case AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION:
+		return "Requested partition does not exist";
+	case AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION:
+		return "Bytes requested is outside the range of partition";
+	case AVB_IO_RESULT_ERROR_NO_SUCH_VALUE:
+		return "Named persistent value does not exist";
+	case AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE:
+		return "Named persistent value size is not supported";
+	case AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE:
+		return "Buffer is too small for the requested operation";
+	default:
+		return "Unknown AVB error";
+	}
+}
+
+const char *str_avb_slot_error(AvbSlotVerifyResult res)
+{
+	switch (res) {
+	case AVB_SLOT_VERIFY_RESULT_OK:
+		return "Verification passed successfully";
+	case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
+		return "Allocation of memory failed";
+	case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
+		return "I/O error occurred while trying to load data";
+	case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
+		return "Digest didn't match or signature checks failed";
+	case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
+		return "Rollback index is less than its stored value";
+	case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
+		return "Public keys are not accepted";
+	case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
+		return "Metadata is invalid or inconsistent";
+	case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
+		return "Metadata requires a newer version of libavb";
+	case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT:
+		return "Invalid arguments are used";
+	default:
+		return "Unknown AVB slot verification error";
+	}
+}
 /**
  * ============================================================================
  * Boot states support (GREEN, YELLOW, ORANGE, RED) and dm_verity
@@ -280,9 +328,9 @@ static unsigned long mmc_read_and_flush(struct mmc_part *part,
 	 * Reading fails on unaligned buffers, so we have to
 	 * use aligned temporary buffer and then copy to destination
 	 */
-
 	if (unaligned) {
-		printf("Handling unaligned read buffer..\n");
+		debug("%s: handling unaligned read buffer, addr = 0x%p\n",
+		      __func__, buffer);
 		tmp_buf = get_sector_buf();
 		buf_size = get_sector_buf_size();
 		if (sectors > buf_size / part->info.blksz)
@@ -321,7 +369,8 @@ static unsigned long mmc_write(struct mmc_part *part, lbaint_t start,
 	if (unaligned) {
 		tmp_buf = get_sector_buf();
 		buf_size = get_sector_buf_size();
-		printf("Handling unaligned wrire buffer..\n");
+		debug("%s: handling unaligned read buffer, addr = 0x%p\n",
+		      __func__, buffer);
 		if (sectors > buf_size / part->info.blksz)
 			sectors = buf_size / part->info.blksz;
 
@@ -349,28 +398,35 @@ static struct mmc_part *get_partition(AvbOps *ops, const char *partition)
 	dev_num = get_boot_device(ops);
 	part->mmc = find_mmc_device(dev_num);
 	if (!part->mmc) {
-		printf("No MMC device at slot %x\n", dev_num);
+		printf("%s: no MMC device at slot %x\n", __func__, dev_num);
 		goto err;
 	}
 
-	if (mmc_init(part->mmc)) {
-		printf("MMC initialization failed\n");
+	ret = mmc_init(part->mmc);
+	if (ret) {
+		printf("%s: MMC initialization failed, err = %d\n",
+		       __func__, ret);
 		goto err;
 	}
 
-	ret = mmc_switch_part(part->mmc, part_num);
-	if (ret)
-		goto err;
+	if (IS_MMC(part->mmc)) {
+		ret = mmc_switch_part(part->mmc, part_num);
+		if (ret) {
+			printf("%s: MMC part switch failed, err = %d\n",
+			       __func__, ret);
+			goto err;
+		}
+	}
 
 	mmc_blk = mmc_get_blk_desc(part->mmc);
 	if (!mmc_blk) {
-		printf("Error - failed to obtain block descriptor\n");
+		printf("%s: failed to obtain block descriptor\n", __func__);
 		goto err;
 	}
 
 	ret = part_get_info_by_name(mmc_blk, partition, &part->info);
 	if (ret < 0) {
-		printf("Can't find partition '%s'\n", partition);
+		printf("%s: can't find partition '%s'\n", __func__, partition);
 		goto err;
 	}
 
@@ -683,7 +739,7 @@ static AvbIOResult read_rollback_index(AvbOps *ops,
 {
 #ifndef CONFIG_OPTEE_TA_AVB
 	/* For now we always return 0 as the stored rollback index. */
-	printf("%s not supported yet\n", __func__);
+	debug("%s: rollback protection is not implemented\n", __func__);
 
 	if (out_rollback_index)
 		*out_rollback_index = 0;
@@ -729,7 +785,7 @@ static AvbIOResult write_rollback_index(AvbOps *ops,
 {
 #ifndef CONFIG_OPTEE_TA_AVB
 	/* For now this is a no-op. */
-	printf("%s not supported yet\n", __func__);
+	debug("%s: rollback protection is not implemented\n", __func__);
 
 	return AVB_IO_RESULT_OK;
 #else
@@ -765,8 +821,7 @@ static AvbIOResult read_is_device_unlocked(AvbOps *ops, bool *out_is_unlocked)
 {
 #ifndef CONFIG_OPTEE_TA_AVB
 	/* For now we always return that the device is unlocked. */
-
-	printf("%s not supported yet\n", __func__);
+	debug("%s: device locking is not implemented\n", __func__);
 
 	*out_is_unlocked = true;
 
diff --git a/doc/android/avb2.rst b/doc/android/avb2.rst
index a072119..4aca7a5 100644
--- a/doc/android/avb2.rst
+++ b/doc/android/avb2.rst
@@ -38,16 +38,22 @@ AVB 2.0 U-Boot shell commands
 Provides CLI interface to invoke AVB 2.0 verification + misc. commands for
 different testing purposes::
 
-    avb init <dev> - initialize avb 2.0 for <dev>
-    avb verify - run verification process using hash data from vbmeta structure
+    avb init <dev> - initialize avb 2 for <dev>
     avb read_rb <num> - read rollback index at location <num>
     avb write_rb <num> <rb> - write rollback index <rb> to <num>
     avb is_unlocked - returns unlock status of the device
-    avb get_uuid <partname> - read and print uuid of partition <partname>
+    avb get_uuid <partname> - read and print uuid of partition <part>
     avb read_part <partname> <offset> <num> <addr> - read <num> bytes from
-    partition <partname> to buffer <addr>
+        partition <partname> to buffer <addr>
+    avb read_part_hex <partname> <offset> <num> - read <num> bytes from
+        partition <partname> and print to stdout
     avb write_part <partname> <offset> <num> <addr> - write <num> bytes to
-    <partname> by <offset> using data from <addr>
+        <partname> by <offset> using data from <addr>
+    avb read_pvalue <name> <bytes> - read a persistent value <name>
+    avb write_pvalue <name> <value> - write a persistent value <name>
+    avb verify [slot_suffix] - run verification process using hash data
+        from vbmeta structure
+        [slot_suffix] - _a, _b, etc (if vbmeta partition is slotted)
 
 Partitions tampering (example)
 ------------------------------
diff --git a/include/avb_verify.h b/include/avb_verify.h
index 1e787ba..5d998b5 100644
--- a/include/avb_verify.h
+++ b/include/avb_verify.h
@@ -1,8 +1,6 @@
-
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * (C) Copyright 2018, Linaro Limited
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef	_AVB_VERIFY_H
@@ -54,7 +52,8 @@ char *avb_set_enforce_verity(const char *cmdline);
 char *avb_set_ignore_corruption(const char *cmdline);
 
 char *append_cmd_line(char *cmdline_orig, char *cmdline_new);
-
+const char *str_avb_io_error(AvbIOResult res);
+const char *str_avb_slot_error(AvbSlotVerifyResult res);
 /**
  * ============================================================================
  * I/O helper inline functions
diff --git a/test/py/tests/test_android/test_avb.py b/test/py/tests/test_android/test_avb.py
index 238b48c..865efbc 100644
--- a/test/py/tests/test_android/test_avb.py
+++ b/test/py/tests/test_android/test_avb.py
@@ -1,6 +1,5 @@
-# Copyright (c) 2018, Linaro Limited
-#
 # SPDX-License-Identifier:  GPL-2.0+
+# Copyright (c) 2018, Linaro Limited
 #
 # Android Verified Boot 2.0 Test