nRF52 Delete bonds while in Bootloader

Question

I'm working on a custom board that uses an nRF52832 module. It has a single button that is used to power the device On/Off and a >= 5sec long press from Off to force enter the bootloader (my fail-case backup). The bootloader can also be entered by the buttonless DFU. 
 I would like to delete bond data when entering the bootloader by the long-press since I cannot provide a separate button for it. I also don't want to use BLE command to do it in case of app failure. 
 I added a bootloader entry case for the long press in static bool dfu_enter_check(void) in nrf_bootloader.c and I would like to delete bonds here, shown below: 
 static bool dfu_enter_check(void)
{
 // If power button is held for >= 5 seconds, then enter DFU
 uint32_t timeout_ticks = nrf_bootloader_dfu_timer_counter_get() + NRF_BOOTLOADER_MS_TO_TICKS(5000);
 while (0 == nrf_gpio_pin_read(PIN_PB_OUT))
 {
 if(nrf_bootloader_dfu_timer_counter_get() >= timeout_ticks)
 {
 NRF_LOG_DEBUG("DFU mode requested via timed button press.");
 
 delete_bonds(); // <-- This
 
 return true;
 }
 }
 
 ...
 
 return false;
} 
 
 My question is, is there a quick and dirty way to do this in the bootloader without having to pull in the entire peer manager?

Zami · Accepted Answer

I suppose one way I could do this is setting a delete-bonds-flag in GPREGRET2. Then if the app is valid it would read the flag, delete bonds, and reset GPREGRET2. ..I'll try this first but I'm open to more suggestions. 
 EDIT: So I got it working but I had to change the bootloader behavior when the power button is pressed as follows: 
 button pressed < 5sec run bootloader normally 
 button pressed >= 5sec set the delete-bonds flag in GPREGRET2 and let the bootloader run normally when released, ie if valid app then it will jump to it. 
 button pressed >= 10sec then stay in the bootloader (delete-bonds flag still set)

nRF52 Delete bonds while in Bootloader

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