Ok looks like it was partially a TrustZone issue. I'm now using the .mbn from sdk 1.0.0 and I can at least read from spidev14.0. But still no dice to actually get the camera to read actual data.
This is the correct pinout from the M0104 J10 to the M0188 J4, yes?
cc680700-34cd-4064-a702-091622e1e012-image.png
What I'm getting now:
voxl2-mini:/$ dd if=/dev/spidev14.0 bs=164 count=1 | hexdump -C
1+0 records in
1+0 records out
164 bytes copied, 0.0010337 s, 159 kB/s
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000000a4