CPU Warnings and Reboot (CB1 + Manta M8P)

I'm seeing warnings on the screen like the following and then some kind of crash dump with the message "Rebooting in 5 seconds..."
There are more warning than these listed... but I can't read them off this tiny screen fast enough.
`
WARNING: CPU: 0 PID: 3039 at sd_recv0xdc/0x374 [8189fs]
`
`
rt[8189fs]: probe of mmc1:001:1 failed with error -123
`
There was a warning something about "card claims to support voltages below defined range"

After some time, the system reboots on its own. There does not seem to be an exact pattern.
Additionally, I'm not getting a WiFi connection even though I defined one in the system.cfg file before plugging in the SD card.
I'm using the Manta M8P and the CB1

Start with the CB1 system image and the system.cfg WiFi configuration, then reproduce the warnings on the Manta M8P while capturing the full boot and crash output instead of relying on the tiny screen. Done means identifying the cause of the mmc1/8189fs failure, preventing the unexpected reboot, and establishing why the configured WiFi connection does not start.

Written by the indexing model from the issue text.