nRF52 single bank: REMOTE DFU INVALID CRC ERROR

[Gordon]

Hi,

I've been trying to get DFU updates working on my device for a while now... I've got the single-bank bootloader compiled and seemingly working (and a combined hex file of sd+bootloader+app works great).

I used nrfutil (3.10.0.14) to create a zip file based on my application:

nrfutil.exe dfu genpkg dfu.zip --application firmware.hex --application-version 0xff --dev-revision 1 --dev-type 1 --sd-req 0x81

I can now upload the zip from my phone, and it gets all the way to 99% and then fails with: REMOTE DFU INVALID CRC ERROR

Any idea what could be causing this? Presumably nrfutil is calculating the CRC (in manifest.json and the .dat file), and this is going straight to the bootloader... What could be confusing things? Is something else part of the crc?

[Gordon]

Unfortunately I can't test it because the binary file is too large (hence the single bank loader). I just checked the bin file, and the crc in the manifest is definitely correct... I did a firmware update using Android (which failed), then dumped the contents of memory and compared the two memory areas. Everything after 0x10010 in the binary (so absolute address 0x2c010 as the binary starts at 0x1c000) seems to be correct, but everything before is trashed - mostly 0x00, with some 0x10, 0x20, 0x40 and few very occasional other values.