Are pages from MBR used during SD_MBR_COMMAND_COPY_BL?

[Clem Taylor]

I'm trying to track down who is erasing and programming 0x800..0xFFF.

Does the SD_MBR_COMMAND_COPY_BL modify 0x800..0xFFF?

I inserted a CRC32 at the end of the MBR (4K-4), at the end of the SD (0x16000-4), at the end of my application and at the end of the bootloader. The CRC at the end of the MBR was added for completeness.

I'm not sure how I got this far and missed it, but when my bootloader swaps in a new bootloader the last two pages of the MBR are getting erased and some stuff is getting left behind.

Before upgrading the bootloader I have:

0x800:	0xffffffff	0xffffffff	0xffffffff	0xffffffff
0xff0:	0xffffffff	0xffffffff	0xffffffff	0x5d9d4f3f <= CRC32(0..4K-4)

Afterwards:

0x800:	0x00000000	0x00016000	0x00002000	0xcdcdcdcd
0xff0:	0xffffffff	0xffffffff	0xffffffff	0xffffffff

As far I can tell this is the result of SD_MBR_COMMAND_COPY_BL. Can someone verify that the bootloader copy command uses 2 pages of the MBR as a scratch space or something?

I don't really need to have a CRC covering 0..4K-4, I mostly did it for completeness. I guess I should not be surprised 0x800..0xFFF is used for something, because it is 0xFF in the softdevice hex and 50% seems like quite a bit of space reserved for future use.

[Hung Bui]

Hi Clem,

Actually, we do use that 2 pages to store some parameters when doing bootloader update for failsafe reason. So, unfortunately, you may have to come back to the solution to store MBR CRC in the bootloader setting page :)

[jokii]

Hi Hung Bui

sometimes my firmware behaves incorrect - I have bonded mobile which seems not be able to connect to nordic device. Both when in whitelist mode and without whitelist, even when bonding data are erased and device is clean. I've downloaded hex from Noric chip and noticed that one difference between working image is modified memory at 0x800. When I've erased that difference problem disappear. I can add that nordic device is frequently resetting by power down, since other HW problems, which can have influence. My question is this safe to erase memory at 0x800 and why this cause problem? I'm using SDK 10 and s110_nrf51_8.0.0_softdevice.hex SoftDevice.

[Hung Bui]

@jokii: Please create another case. And please describe with more information on the mobile you used. The hardware board you used. Also attach a sniffer trace log if possible.