I think it would be a good idea to put a warning message on this switch.
After a nice setup from a X95 max + 4/64 with a working display etc, I activated this switch, The box runs on the newest firmware (summer 2020) and CE 9.2.5
After the reboot no reaction, no light, no logo, nothing.
Measuring inside the box showed 5 and 3.5 V where needed but no reaction.
Then I found out I was not alone with this problem.
It seems 2 pins need to be shortened but still try to find the whole process what is needed to revive the box.
You can check the thread about BL301 problems and see that there are not cases of bricking devices. The thread from xda you mentioned mixes BL301 and ceemmc tool that is only supported in a limited number of devices. To provide the help needed to sort out this kind of issues we need logs. In your case probably UART logs to find out why it isn’t booting correctly.
The shorting of the pins is a well known “last resort” way of reviving the box but you still need the correct firmware for your device.
CoreELEC has been installed onto eMMC using their "ceemmc" tool. CoreELEC runs just fine.
Device is now unable to boot Armbian from either SD card nor USB.
Can't restore stock firmware: Burn Card Maker throws an error when writing SD card. Also, manually created SD card gives a black screen.
It is clear written on ceemmc guide that the internal install need to be removed before a Android update is performed!
it is nice to know the box is not dead, just does not show anything on the screen and the red light from the audio port nor the display show any signs of life. I looked through the mentioned thread and found a couple guys who solved the problem by shorting the pins. Now I just need to figure out which pins.
Logs, I do not have since the box does not work, the inside can be seen here: