As this thread is already late, it is now necessary to reinstall the Bios with the method you describe. The procedure is the same and only logically changes the files to flash.
You need Chuwi to put you a link to download the correct Bios files for your tablet.
To do this, you have to write to service@chuwi.com indicating that you have bricked the tablet when updating the Bios, put your serial number and wait at least until February 11 for Chuwi to return to work since, after Chinese New Year celebrations, the return to work has been delayed due to the effects of the coronavirus.