Hi, I have added a feature to read/write eMMC in 1-bit mode. Needs 4 signals only: nRST, CLK, CMD, DAT0 (not counting GND, Vcc, Vccqq). I have pushed the code into ‘emmc-isp’ branch of my fork. If there is any interest, I can raise a PR or sometihg.
Best regards, Alex