Just wanted to circle back and share an interesting datapoint…
I’m only seeing the described error above (spl: mmc init failed: err - -19) with GHI BBBs that have the MT32 eMMC part. Related to my recent post about a SEEED Studio BBB I had bought last month from DigiKey that has a MT32 eMMC part on it, the older 2015.1 U-Boot code we’re using does NOT encounter any mmc init errors at boot time, it just boots up “as usual” for us into Linux, no issues. This was counter to my expectations and just wanted to share here in case anyone else bumps into a similar situation.