Tablet dead after booting from Windows 10 pen drive

I've inserted my pen drive with Win10, and a keyboard, onto a hub with the OTG cable that came with the tablet. I opened the BIOS with Esc, booted from the pen drive. It was stuck with the teclast chinese letters logo for about 2-3mins before displaying a Windows error message / blue screen with a :( face and the following error code: ACPI_BIOS_ERROR. I turned it off by pressing the power button for 8 seconds, then tried to boot again. Nothing. Zero. No reaction. I've plugged it into the charger and it's still dead. What the actual hell? What have I done that I can't even power the tablet on? I hope I didn't hardbrick it.... What happened and what can I do?

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