Custom RAMDLD implementation for Motorola P2K phones on Neptune LTE originally written from scratch by @muromec, fork of the https://github.com/muromec/lte-hitagi repository.
sudo apt install gcc-arm-none-eabi
cd LTE-Hitagi
make
Please use the Flash Terminal utility: https://github.com/EXL/FlashTerminal
cd FlashTerminal
sudo ./FlashTerminal.py -v -l
Thanks to @muromec