Wennimo Now I've paused the reset and am at the boot loader screen with the yellow warning sign. I don't know what to do from here or why this happened in the first place.
After trying, I cannot go into recovery by holding the power and lower volume buttons.
What happens if, at the "Press power button to resume" screen, you press and hold the power button for a long time, like 30+ seconds, and then, as soon as the screen goes black, press and hold the volume-down button? On my device that gets me into fastboot.