You can find the .bin at http://qhtn4w2q36dojls2.onion/data/iso/chromeos_10176.76.0_terra_recovery_stable-channel_mp-v2.bin
Trying with buster's cfdisk now. . .doesn't seem to happen, cfdisk does not have an assertion error with debian buster / util-linux 2.32.1-0.1
