Hello… versioning B6 has the eMMC at 2GB, I think. The latest Debian images from this forum, beagleboard.org, or rcn-ee.com all have images larger than 2GB (I think).
Anyway, have you tried the reset button yet? Maybe booting from SD Card is what it is supposed to do.
It should boot from SD Card by itself if you are using one of the newer images.
Seth
P.S. I could be wrong but I will continue to try to help. oh!
Here is something that may help: Debian 11.x (Bullseye) - Monthly Snapshots
Those are the newer images that are testing images for the BBB.