Softdevice 7 does not boot unless flash space gap is filled 0xFF

RE: Softdevice 7 does not boot unless flash space gap is filled 0xFF

hjz — Tue, 24 Mar 2020 13:55:53 GMT

Thanks Amanda, this seems to be issue. Confirmed this by manually editing the MBR_BOOTLOADER_ADDR.

RE: Softdevice 7 does not boot unless flash space gap is filled 0xFF

Amanda Hsieh — Tue, 24 Mar 2020 10:52:01 GMT

Hi,

For SoftDevice S132v5.0.1 running against SDK 14.0.0, you do not need to add the gap-fill value.

It's started from S132 v6.1.1 same with S140 v6.1.1. The change happens between MBR v2.2 and v2.4.x. You can check the release note of the softdevice to find the version of the MBR.

-Amanda H.

RE: Softdevice 7 does not boot unless flash space gap is filled 0xFF

charles — Mon, 23 Mar 2020 17:19:28 GMT

Is this official confirmation that the gap-fill value has no effect on SoftDevice S132v5.0.1 running against SDK 14.0.0?

RE: Softdevice 7 does not boot unless flash space gap is filled 0xFF

Amanda Hsieh — Mon, 23 Mar 2020 17:15:12 GMT

Hi,

From SDK v15.3 we changed the bootloader start address register (NRF_UICR_BOOTLOADER_START_ADDRESS) from NRF_UICR_BASE + 0x14 in the UICR to MBR_BOOTLOADER_ADDR (at 0xFF8) in the MBR.

Please see this post and this.

-Amanda H.

RE: Softdevice 7 does not boot unless flash space gap is filled 0xFF

charles — Fri, 20 Mar 2020 14:17:22 GMT

Just to be very explicit, our build system does the following:

1. Compile and link our application into an elf file.

2. objcopy the application elf file to a hex file.

3. mergehex (nrf command line tool) the SD hex file and the application hex file.

4. objcopy the merged hex file to a bin file.

Step 4 is what we're talking about here, where the gap-fill value causes SoftDevice to crash on boot before coming near the application code.

We'd love an explanation if you have one, but the most important piece of information we need is whether or not SDK14.0.0 + S132v5.0.1 are resilient against this approach. We didn't see any errors when testing but that's a weak hypothesis compared to a root cause analysis.