code review fixes

Author: bigbrett

docs/firmware_update.md

@@ -203,14 +203,14 @@ more detail on the `--header-only` sign tool option.
 #### Monolithic updates
 
 The self-update mechanism can be used to update both the bootloader
-**and** the application firmware in a single atomic operation. Because
+**and** the application firmware in a single operation. Because
 `wolfBoot_self_update()` copies `fw_size` bytes from the update image to
 `ARCH_FLASH_OFFSET`, a payload that is larger than the bootloader region
 will spill into the contiguous BOOT partition, overwriting whatever
 application image was there previously.
 
-No wolfBoot code changes are required — only the update payload needs to
-be assembled differently. The payload is constructed by concatenating the
+To enable this behavior, set `SELF_UPDATE_MONOLITHIC=1` in your build
+configuration. The payload should be constructed by concatenating the
 new bootloader binary with the new signed application image and signing
 the result as a wolfBoot self-update. Note that the user must ensure that padding
 is supplied such that the header of the new signed app image will be located

tools/test.mk

@@ -272,7 +272,7 @@ test-sim-self-update: wolfboot.bin FORCE
 # the contiguous boot partition.
 test-sim-self-update-monolithic: wolfboot.bin test-app/image_v1_signed.bin FORCE
 	@echo "=== Simulator Monolithic Self-Update Test ==="
-	@# Create dummy bootloader (0xAA pattern, exactly BOOTLOADER_PARTITION_SIZE)
+	@# Create dummy bootloader (0xAA pattern, exactly bootloader region size: WOLFBOOT_PARTITION_BOOT_ADDRESS - ARCH_FLASH_OFFSET)
 	$(Q)dd if=/dev/zero bs=$$(($(WOLFBOOT_PARTITION_BOOT_ADDRESS) - $(ARCH_FLASH_OFFSET))) count=1 2>/dev/null | tr '\000' '\252' > monolithic_dummy_bl.bin
 	@# Concatenate dummy bootloader + signed app image to form monolithic payload
 	$(Q)cat monolithic_dummy_bl.bin test-app/image_v1_signed.bin > monolithic_payload.bin