I’m on a Boox Go Color 7, i patched the boot.img then i flashed it using edl (adb reboot edl) and now i can not get it back into edl. Fastboot is ‘broken’—getvar works, but set-active and reboot fastboot return unknown command or unbootable components. I’ve tried every volume button combo to hit EDL (9008). The device is currently a brick that only shows the Onyx logo or a black/white screen. Has anyone found a way to force a slot-switch or EDL handshake?
update: i got an edl cable and switched to slot b and it is still in a bootloop
update: after speaking to ai for a long time and going in circles. i flashed the stock boot.img and then i tried booting still bootlooped, then i switched to slot b and it still bootlooped, then i switched back to slot a and it worked! 
(Kind of awkward that I am speaking to myself.)