Caveat: I won't follow up on any questions. Do this at your own risk. You don't need an OTG cable.
If you can't boot into fastboot mode:
- run `./update partition boot <boot.img>` as root
- run `./update bulkcmd "reset"` (including quotes) as root
- You should now be in fastboot mode
The first step in the quote above flashes boot.img to the boot partition on the emmc.
The second step reboots the device.
This probably won't result in rebooting to fastboot (the bootloader version of fastboot).
update bulkcmd "reset"
Using this command:
update bulkcmd "fastboot"
would immediately load bootloader fastboot (without even rebooting).
And it isn't necessary to flash the boot partition first in order for this to happen.
Notice that there are no questions in this reply, so you won't have to violate your pledge not to follow up on any questions.