Enable sdcard detect on MKS GEN_L board - makerbase-mks/MKS-H43 GitHub Wiki
If used MKS HH43 with MKS Gen_L V1.0/V2.1 board, and want to enable the sdcard detect function, you should config on Marlin source: At the end of the "pins_MKS_GEN_L.h" file, add:
#if ENABLED(DGUS_LCD_UI_MKS)
#ifndef SD_DETECT_PIN
`#define SD_DETECT_PIN 49`
#endif
#endif