No, I was not able to fix it. Tried Esc, F2, Fn+F2, F12 or Del to get into the BIOS and then “(F2 + Enter +) F3 + Enter + F4 + Enter” to reset the BIOS.
Have not checked the HDMI output, since I don’t have a micro-HDMI cable. (In another thread for another model but the same issue, the HDMI output also remained black.)
This bug is a bit unexpected since Chuwi advertises Linux compatibility (at least on Chuwi’s and Aliexpress’s websites). This is clearly a factory defect in my opinion, even without the Linux compatibility claim.
Still have not heard anything from Chuwi support (firstname.lastname@example.org).
NOTE There is a similar thread at https://techtablets.com/forum/topic/chuwi-lapbook-pro-8gb-i-need-a-way-to-reset-bios-settings-to-factory-defaults/.