Writing to bootloader flash region from the application?

RE: Writing to bootloader flash region from the application?

Hung Bui — Thu, 22 Jul 2021 10:07:36 GMT

Yes your hypothesis is correct. When flash protect is commented out, the write/erase should pass.

It's the reason why I asked to try testing the same when you don't use the bootloader.
Just to verify that the code you used to write to the desired address is correct and works without the bootloader. Then we know that the bootloader does something to the flash area (which it should not).

RE: Writing to bootloader flash region from the application?

SwEngineer007 — Wed, 21 Jul 2021 20:39:17 GMT

Hi,

WRP - Write protection

The bootloader applies the write protection using the following and experiences no issues (right now it's commented out):

nrf_bootloader_flash_protect( START_ADDR, BOOTLOADER_SIZE, false )

Where START_ADDR = 0x2'6000 and BOOTLOADER_SIZE = (0xF'DFFF - START_ADDR + 1)

Then in the application layer, any attempt to write to the last page of the bootloader partition (which is not used, all 0xFF's) at the test address ( BOOTLOADER_SIZE - PAGE_SIZE ) nothing is erased or written.

My hypothesis is based on other ARM MCU's, but may or may not be correct, but it is essentially this:

1. When nrf_bootloader_flash_protect is commented out, erase/write should pass and write to the test address

2. When nrf_bootloader_flash_protect is active, it should exhibit a fault.

So, the issue is writing to the flash from the app layer to the bootloader region and in test case #1, nrf_fstorage_write( ) and nrf_fstorage_erase( ) erases nothing and writes nothing to the test address.

RE: Writing to bootloader flash region from the application?

Hung Bui — Wed, 21 Jul 2021 12:28:57 GMT

Hi,
Could you please explain what exactly you meant by "WRP" ? Did you mean the ACL peripheral ? Could you give more information on how you turn it off an on.
Have you removed the protection in the bootloader ?

If you try to test the same code without the bootloader flashed do you have any problem ?