how to enter Bootloader mode

[Chaw]

Hi, Nordic

I check this: devzone.nordicsemi.com/.../ , first, it will work when I follow this article. Then I have 2 questions:

1. it said "If the bootloader LED is not lit, try pressing Button 4 during startup, this will put the device into bootloader mode".
   where can I found these code? (press button 4 to enter to bootloader mode)

   If I want to change the way to enter bootloader mode, how can I do?

   after DFU done, when I download new bootloader, it show "ERROR: The area to write is not erased.", this time, if I want to update bootloader, only can DFU?

2. I check, when DFU done, bootloader->app, now APP is running, can I add code to make nRF52 enter to bootloader mode? If yes, how can I do?

Plz help me. Thanks.

[frogofmagic]

About Q1, if you want update bootloader by PC, you need to erase chip first.

[bjorn-spockeli]

Hi Chaw, my colleague Ole suggested an approach for changing the way you enter bootloader mode in the other question that you posted, here is the link. Let me know if there is something that is unclear.

[Chaw]

Hello, for other issues, could you explain? where can I found these code? (press button 4 to enter to bootloader mode)

[bjorn-spockeli]

If you're using the bootloader in SDK v12.x.0 then you will find the code in the nrf_dfu_enter_check() function in the nrf_dfu.c file. However, note that this is only done once on startup, i.e. you have to hold the button while you turn on the device.

[Chaw]

ok, thanks, I checked.