2.20 -> 2.21
corrected solder pads for SD card connector
adjusted BOM
2.30
changed all components to THT ( SD card holder SMD&THT)
added jumper bank for System1 to protect PCB in case of faulty connection
BOM_230_1
changed D3,D4 to available part C3058
BOM_230_3
changed C1,C6, S2 to available part