@djhnsn
Yes, I have a bit of experience with mis-matched uboot-OS, different than you
I suppose it could be a hardware problem, but you are sometimes getting boots - emmc recognition
I assume you have checked that emmc is seated in its socket, or tried unplug - replug
You could setup pbp like mine, until you find a satisfactory uboot,, emmc 1st 16M blanked, mbr restored
Then, the only uboot is on SD, lsblk and dmesg | grep mmc to see what is happening
Then, try 'satisfactory' uboot ONLY on SD to see if will boot emmc (blank mbr on SD, note sector #s)
Sometimes a couple second pause seems to make a difference, I don't know how to set this up
-----
(the point to doing all uboot experimentation on SD, if you screw up or something badly mis-matched, easier to recover)
Yes, I have a bit of experience with mis-matched uboot-OS, different than you
I suppose it could be a hardware problem, but you are sometimes getting boots - emmc recognition
I assume you have checked that emmc is seated in its socket, or tried unplug - replug
You could setup pbp like mine, until you find a satisfactory uboot,, emmc 1st 16M blanked, mbr restored
Then, the only uboot is on SD, lsblk and dmesg | grep mmc to see what is happening
Then, try 'satisfactory' uboot ONLY on SD to see if will boot emmc (blank mbr on SD, note sector #s)
Sometimes a couple second pause seems to make a difference, I don't know how to set this up
-----
(the point to doing all uboot experimentation on SD, if you screw up or something badly mis-matched, easier to recover)