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Bootloader startup issue about power

Hi

  1. I have custom board with nrf52832. I have lion batery and 3.3V ldo for powering device. I attached shematic.
  2. For preventing lion battery decreasing below 3V, i used a 3.1V voltage detector ic. This detector (STM1061N31WX6F) makes LDO enable pin logic low so everything stops. Here i have 1Mohm pullup resisor.
  3. Detector ic disable ldo 3.1V and re eanble 3.3V. If i load bottloader code detector ic still working same but nrf52832 hangs. Everything is fine without adding bootloader code.
  4. I dont have problem loading apk over mobile with dfu, its ok.
  5. I have 50 circuits for preproduction. I have 50 product.
  6. When i  load softdevice and load "bootloader_secure_ble". I can see DFU_Targ with mobile but when i click no service appear.
  7. When i rise batery voltage starts working, I can see services. But this happen with different batery voltages with different products.  One 4V, another 3.8V, another 4.3V.  But start to see 3.3V ldo output with battery voltage 3.3V.
  8. I short pullup resistor of LDO enable, load apk over mobile device and leave shorting pullup (1Mohms), device hangs. Nothing advertise.
  9. My apk is modified "ble_app_uart ". I add pwm, adc, low power mode and some other things. They all fine.

Its something very strange but i cant find what differs with starting device with "ble_app_uart " or with "bootloader_secure_ble".

Is there any difference for Power on Reset of DC DC conveter or do you have any idea.

Thanks

FerhatShematic