after testing android 11 image on vim 3 , and installing images, the board ceased working , and no longer recognised by pc. even the power led don’t turn on , what shall I do ?
Hello, Try another power supply. Also, look in to M-register mode, see here.
Hi, if the board is lost, connect the board to the computer and run the UBT flashing tool, then quickly press the middle button three times, the board should be detected, use a tested USB cable.
@Vladimir.v.v @RDFTKV this isn’t a particular hardware issue, another developer also faced this issue, presumably after flashing the uboot to the eMMC (from AOSP),
eg.
so this might be something more critical…
maybe Krescue could be of use here, @taimed did you try using Krescue ?
I’m not saying that this is a hardware problem, it’s just an unsuccessful firmware built on Android 11.
Does that also mean that S-Register cannot help.
krescueis useless in this problem, even the computer doesn’t recognise it when i execute lsusb
Measure the voltage at the pin legs of the board, test points, so to speak, is there a voltage?
Even with M-register (MASKROM)?
Be great if you could get Krescue on spi.
what are the test points ?
I mean gpio, you can see it according to the diagram.
there is no voltage 
Check your PSU and cable, is there a problem with it?
works so fine , besides changed it many time but same problem
Is the cable okay too?
Yes
You can visually inspect the board, perhaps some diode is out of order, burned out, for example.
nothing to be noticed on the board
There are no miracles.
Check the voltage at the board input, there may be a problem with the tipe-c port itself.