Secure bootloader upload failed: UNKNOWN (8202)

[Gordon]

Hi,

I've been trying to integrate the secure bootloader witrh SDK12 into my device, which had been working fine with the old bootloader and SDK11.

I've swapped everything over, and finally got the bootloader to boot into my application. The only real gotcha was that the bootloader setting had changed, so if I just merged all the hex files it failed to load the application.

To fix that, I just removed the bootloder settings from 0x3F000 and tweaked the check in nrf_dfu_app_is_valid to allow the app even if bank_0.bank_code was 0. Is there a better way - like a way to build a hex file for the correct settings?

Anyway, with that change, and the bootloader running, I get upload failed: UNKNOWN (8202) when trying to upload from the Nordic Android app. The device itself has lit the LED showing that it's connected.

So how do I find out what Error 8202 means? I don't see any obvious mention of it (or 200A, the hex version) in the source.... And any thoughts on how it can be fixed? I figure if there was some version or encryption mismatch then it would have come up with a 'proper' error?

thanks!

[bjorn-spockeli]

Just to clarify: You're not trying to update from the legacy bootloader from SDK v11 to the Secure bootloader from SDK v12? Your only trying to flash the Secure bootloader and an application as a merged image with the valid app flag set right?

[Gordon]

Yes, it's all SDK12. I have a merged image with an application that works, an a self-compiled secure bootloader that runs when power is applied with a button pressed. The issue I'm having is when I try to use that bootloader to upload a new application binary over BLE (also SDK12 - in fact identical to the firmware that's already on there and working).

[bjorn-spockeli]

Do you see the same behavior with the test images that are provided in the SDK? Which Android app are you using ( nRF COnnect or nRF Toolbox) and which version is it?

[Gordon]

I'm using nRF toolbox, 1.18.4. nRF connect 4.5.0 just connects and for a few seconds and then disconnects without any warning. I haven't tried the test images, but I'd imagine that they would be ok. Is it vital that bank_0.bank_code is 1? I'd sort of assumed that all that info would get overwritten after a successful DFU?

[bjorn-spockeli]

Is the device resetting to the application when it disconnects or is it still in bootloader mode? If you want the bootloader to start the application without having to perform DFU, then yes, s_dfu_settings.bank_0.bank_code must be set to NRF_DFU_BANK_VALID_APP (i.e. 0x01). Yes, the bank code will be overwritten when you update the application.