I modified RepRapFirmware and update the pinout, I was able to compile and upload to DaVinci Jr. mainboard. I can connect through USB, and get chitchat. unable to access sd card. RepRapFirmware store many information on onboard sd card including homing gcode etc, so I was not able to move axis. I have not change RepRapFirmware to drive LCD yet, the LCD lights up, no black bar but no display either.
(Da Vinci 1.0, Jr. 1.0 RAMPS, miniMaker) X4, (Creality CR-10S, CR-10 mini, Ender-3) X4, Anycubic MEGA X4, Anycubic Chrion X1, ADMILAB Gantry X2 (MonoPrice Maker Select V2, Plus, Ultimate)X4--Select mini X1, Anycubic photon X4, Wanhao duplicate D7 X1.
iNSTONE Inventor Pro X2, CTC Dual X2, ANET-A8, Hictop 3DP-11, Solidoodle Press, FLSUN I3 2017X1