eMMC Failed. Why?
Summary
ZipCPU's blog post details debugging an eMMC boot failure on a KlusterLab FPGA board. It explains how a CMD6 command appeared to work while a subsequent CMD19 (BUSTEST_W) failed to elicit a response, analyzes the root cause in the eMMC front end and boot protocol, and describes a fix that resets the logic when data is transferred. The piece also discusses the use of an internal logic analyzer, AutoFPGA tooling, and a cost-focused view on hardware debugging versus simulation.