Hi All,
We're experiencing a strange boot issue after replacing the eMMC in a current product. Background - we are trialling a suggested (drop in replacement) Kingston eMMC part as the original is no longer available. Our product has two dip-boot switches fitted that will either put the device into factory serial download mode or normal run mode. Only one is actually used.
As normal a new unprogrammed imx7d will be in factory serial mode by default until it's been flashed and the OTP fuses set - in our case bank 1 word 3 = 0x10002820, after which the only way to reprogram the product is to use the on-board boot dip switches to force it back into factory serial mode.
Here's the issue.. with a number of known good working PCBs we had the old eMMC replaced with the new 'suggested' drop-in replacement eMMC to verify that it's OK to use them in production; but the new eMMC are keeping the boards in permanent factory serial mode!
u-boot detects the new eMMCs fine, the fuse bits are still set to boot as normal (question to clarify - the OTP boot fuse bits are actually in the imx processor correct?) which were actually set when the boards first went in to service, u-boot DFU and UMS work fine. So what could be causing the boards to be stuck in factory serial mode after programming regardless of the dip-boot switch settings?
How can replacing the eMMC cause the boards to be struct in factory serial mode? It's just a slab of memory, all boot fuses are in the imx7.
Kind regards.