How to turn on bootloader mode on LPCXpresso55S69?

[tarun1]

I need to flash the following app onLPCXpresso55S69 board: https://github.com/Nitrokey/nitrokey-3-firmware/blob/main/docs/lpc55-quickstart.md.

I am trying to put my new LPCXpresso55S69 in bootloader mode to flash an application. I followed the steps outlined in the following link (https://os.mbed.com/teams/NXP/wiki/Updating-LPCXpresso-firmware), but unfortunately, it did not resolve the problem. I keep do not get any output either in `lpc55 ls` or `mboot info` after connecting the USB. 

[tarun1]

Hi @ZhangJennie, I updated the CMSISDAP through LPCScrypt using these instructions https://os.mbed.com/teams/NXP/wiki/Updating-LPCXpresso-firmware. Now when I do `lsusb`, I get `Bus 002 Device 003: ID 0d28:0204 0d28 DAPLINK CMSIS-DAP Serial: ...`. However, I still see nothing on the command `lpc55 ls` (https://github.com/lpc55/lpc55-host). I am trying to get it to work as the following app requires it to flash it to the board: https://github.com/Nitrokey/nitrokey-3-firmware/blob/main/docs/lpc55-quickstart.md.

Based on the product id in the application's documentation that I am trying to run, I assume they are assuming MCU-LINK debug probe instead of LPC-link2 which LPCXpresso55S69 has. Do you have any suggestions for me on how I can flash this app on board? 

[ZhangJennie]

Hi tarun1 

the out-of-factory LPCXpresso55S69 demo board has CMSIS-DAP debug firmware, we can use this debug interface with most of common development environment, for instance, MCUXpresso IDE, Keil, IAR IDE,etc. If the debug firmare is corrupt during using, we can use LPCScrypt to update it to CMSISDAP or Segger Jlink interface. In order to use LPCScrypt updating the firmware, we must set the board to DFU mode 

Then connect board via debug interface(P6), open LPCScrypt to update the firmware

Hope this helps,

Jun Zhang