Bootloader and nRF Connect can't resume DFU

RE: Bootloader and nRF Connect can't resume DFU

tesc — Wed, 30 May 2018 15:06:19 GMT

Hi,

Thanks to your report and detailed descriptions our software engineers have identified an issue: If the DFU is aborted at one particular moment, in-between two objects, it may enter the state that you are experiencing.

It only happens on disconnect + reconnect, as that does not trigger a reset of the DFU target.

The problem is that the connection is lost immediately after a create_object, and when the connection is reestablished the DFU controller performs an execute before resuming the update. They propose fixing it by resetting the settings on disconnect, either through (a potentially modified) nrf_dfu_settings_init(), or as you suggested by doing a reset.

Regards,
Terje

RE: Bootloader and nRF Connect can't resume DFU

Cyril — Wed, 30 May 2018 07:11:24 GMT

Another weird thing is that the BLE disconnection is not always notified to nrf_dfu_ble.c (event BLE_GAP_EVT_DISCONNECTED).
When not notified, we have to wait for the bootloader watchdog to reset the bootloader which is, to my mind, too long to resume DFU.

RE: Bootloader and nRF Connect can't resume DFU

Cyril — Tue, 29 May 2018 13:19:44 GMT

Hello,

Also sorry for the delay, I'm not totally focused on the bootloader right now...

Correct, if I provide a different DFU package it works (bootloader settings are not re-used).

I tried to replicate the bug using the examples you provide along with nRF Connect for Android (OnePlus 3T and OnePlus 6). I flashed my PCA10056 with the secure BLE bootloader and tried to upload the example image (hrs_application_s140.zip). I killed nRF Connect while uploading the image and after a few tests, I had the same bug.

More information

- It seems to appear when the bootloader doesn't reset at all after being disconnected: advertising resumes as expected, then I re-connect and try to send the same image, and got OPERATION_NOT_PERMITTED.
Then even if it resets several times, I'm not able to send the same image and got OPERATION_NOT_PERMITTED each time I try to send the image.
- But, if after being disconnected during upload, it resumes advertising but then reset (before reconnected and trying to send the image), the bug is not present anymore. Probably a variable not being reset correctly when disconnected.

One workaround in the short-term would be to reset the bootloader when disconnected.

Best

RE: Bootloader and nRF Connect can't resume DFU

tesc — Tue, 22 May 2018 12:04:43 GMT

Hi,

First, I am sorry for the late response on this one.

Reading between the lines it looks like you get it to work if you provide a different DFU package from the one you used when it fails. Can you confirm that?

Can you provide a hex dump from when this has happened? ("nrfjprog --readcode filename.hex" for dumping the flash contents to a file named "filename.hex".) If you do not want to share this publicly then please create a private ticket and refer to this thread.

Regards,
Terje

RE: Bootloader and nRF Connect can't resume DFU

Cyril — Mon, 14 May 2018 10:07:38 GMT

This bug can be reproduced quite easily, I killed nRF Connect for Android while performing the upgrade and after several times, I got the same bug.