RE: bootloader only enters DFU when using a breakpoint due to watchdog timeout.

SebastianA — Wed, 28 Apr 2021 11:41:08 GMT

Yes, that was it!

Thanks!

RE: bootloader only enters DFU when using a breakpoint due to watchdog timeout.

Sigurd — Wed, 28 Apr 2021 10:23:38 GMT

Hi,

I suspect this might be caused by a bug in the SDK.

Could you try the fix described by Einar in this post? https://devzone.nordicsemi.com/f/nordic-q-a/67267/watchdog-reset-during-bootloader-dfu/275769#275769

RE: bootloader only enters DFU when using a breakpoint due to watchdog timeout.

SebastianA — Tue, 27 Apr 2021 17:35:18 GMT

Yes, NRF_BL_DFU_ENTER_METHOD_GPREGRET was turned on in our project otherwise the bootloader wouldn't get to the mentioned breakpoints. Our project is a copy of the secure_bootloader example, with the mentioned changes in sdk_config.h.

I now turned on NRF_BL_DFU_ENTER_METHOD_GPREGRET in the open_bootloader/pca10056_usb_debug example and tried it.

I get the same behaviour with that bootloader. The log says:

<info> app: Open USB bootloader started
<debug> app: In nrf_bootloader_init
<debug> nrf_dfu_settings: Calling nrf_dfu_settings_init()...
<debug> nrf_dfu_flash: Initializing nrf_fstorage_nvmc backend.
<debug> nrf_dfu_settings: Using settings page.
<debug> nrf_dfu_settings: Copying forbidden parts from backup page.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<info> nrf_dfu_settings: Backing up settings page to address 0xFE000.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<debug> app: Enter nrf_bootloader_fw_activate
<info> app: No firmware to activate.
<debug> app: App is valid
<warning> nrf_dfu_settings: No additional data erased
<info> nrf_dfu_settings: Backing up settings page to address 0xFE000.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<debug> app: Running nrf_bootloader_app_start with address: 0x00001000
<debug> app: Disabling interrupts. NVIC->ICER[0]: 0x0
<info> app: Open USB bootloader started
<debug> app: In nrf_bootloader_init
<debug> nrf_dfu_settings: Calling nrf_dfu_settings_init()...
<debug> nrf_dfu_flash: Initializing nrf_fstorage_nvmc backend.
<debug> nrf_dfu_settings: Using settings page.
<debug> nrf_dfu_settings: Copying forbidden parts from backup page.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<info> nrf_dfu_settings: Backing up settings page to address 0xFE000.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<debug> app: Enter nrf_bootloader_fw_activate
<info> app: No firmware to activate.
<debug> app: App is valid
<debug> app: DFU mode requested via GPREGRET.
<info> nrf_bootloader_wdt: WDT enabled CRV:65536 ticks
<info> nrf_bootloader_wdt: Starting a timer (62336 ticks) for feeding watchdog.
<debug> app: timer_activate (0x20000038)
<debug> app: in weak nrf_dfu_init_user
<debug> app: timer_stop (0x20000028)
<info> app: Entering DFU mode.
<info> app_timer: RTC: initialized.
<debug> app: Initializing transports (found: 1)
<debug> nrf_dfu_serial_usb: Initializing drivers.
<debug> nrf_dfu_serial_usb: Starting USB
<debug> nrf_dfu_serial_usb: USB Transport initialized
<debug> nrf_dfu_flash: Initializing nrf_fstorage_nvmc backend.
<debug> app: Enter main loop
<info> nrf_dfu_serial_usb: USB power detected
<info> nrf_dfu_serial_usb: USB ready

<info> app: Open USB bootloader started
<debug> app: In nrf_bootloader_init
<debug> nrf_dfu_settings: Calling nrf_dfu_settings_init()...
<debug> nrf_dfu_flash: Initializing nrf_fstorage_nvmc backend.
<debug> nrf_dfu_settings: Using settings page.
<debug> nrf_dfu_settings: Copying forbidden parts from backup page.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<info> nrf_dfu_settings: Backing up settings page to address 0xFE000.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<debug> app: Enter nrf_bootloader_fw_activate
<info> app: No firmware to activate.
<debug> app: App is valid
<warning> nrf_dfu_settings: No additional data erased
<info> nrf_dfu_settings: Backing up settings page to address 0xFE000.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<debug> app: Running nrf_bootloader_app_start with address: 0x00001000
<debug> app: Disabling interrupts. NVIC->ICER[0]: 0x0

I can also get it to work in the same way by adding a breakpoint in the right place and pressing continue. Then it stays in DFU mode until I ask it to start the application via the ABORT command over the USB connection.

RE: bootloader only enters DFU when using a breakpoint due to watchdog timeout.

Sigurd — Tue, 27 Apr 2021 14:03:15 GMT

Hi,

[quote user=""]After around five seconds I reset it with NVIC_SystemReset and expect to get back to DFU mode. That doesn't happen, the application starts again.[/quote]

I assume you have NRF_BL_DFU_ENTER_METHOD_GPREGRET set to 1 in sdk_config.h in the bootloader project?

Could you use the bootloader project with _debug suffix, i.e. pca10056_s140_ble_debug, and check the nrf_log for why it doesn't stay in DFU mode?

(If you are using SES to view the RTT log you might need to set NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED to 0)

It should print "DFU mode requested via GPREGRET." in dfu_enter_check() function ...