RunCPM: Arduino Due + SD Adapter not working

It appears the SDFat support has changed for the Arduino Due, and RunCPM needs to initialize the card differently than previously.

The two changes that need to be made are:

1. DO NOT use SdFatEX. Instead, line 4 of due.h reads: SdFat SD;
2. Run the SD card at 25MHz. At line 86 of RunCPM.ino, I inserted:

#elif defined board_due
  _puts("Initializing Arduino Due SD card.\r\n");
    if (SD.begin(22, SD_SCK_MHZ(25))) {

With those two changes, everything started working.

This was tested with this Arduino SD Card Adapter: https://www.amazon.com/gp/product/B07QQBBL6S

And connected according to this diagram: https://forum.arduino.cc/index.php?topic=132130.0 (VCC on the adapter is connected to 5V on the SPI header. CS is tied to ground.)

The changes are in my fork at https://github.com/tomxp411/RunCPM