820-02020 exclamation mark after start


got this A2338 with the exclamation mark after the start

So i forced it in to the DFU mode

1. download system ok
2. copy ok
3. extrract ok
4. install ok and ends in error

tryed rvieve and restore but in the end got Error 2006 0x7d6 (failed to restore device in recovery mode)

the cable is a known good cable
the taregt was only on batterie and second try with poer cord

what means that 2006 error ?

is it worth to replace the NANDS. can this help? we replaced another devide already with 2TB nands. that works good


using restore i get the Error 0xFAD 4013, found theat:
4013 / 6 - errors indicate bad NAND Sysconfig or wrong position.

that means for me i have to solder out the nands and flash with p13 the firmware, solder back and try then with DFU to flash the bridge OS

is that logical for you?


Staff member
Since M1, you don't need to initialize the NANDs.
Just place them in the same position, as removed from scrap board (same model).


ok, yes right.

By the way. I have the same model where the client needs the data.
if i transplant the ssd in same position from the (client with data) to this board. after this brisge os (revive) will i can read the data out?
can have this sucess?


i swapped the nands and chose the 2TB version. i have done this many times but with this device i always get 4013 as an error in the dfu. the position is correct, i have checked this by desoldering and reading, the content is also exactly the same as the source file.

Then I soldered the original nands back in and everything was as before.

The problem must be in the motherboard somehow.

with the 2TB and the original NANDs:
The DFU process goes something like this

5V 250mA
then load the software
unzip the software
install the software, here about 45%.
then switch to 20V approx. 250mA
after a while 20V approx. 188mA
only the apple is visible on the target device, no charging bar
After another while the ampmeter restarts at 5V 0A, this cycles about all 20sec
On the source PC the bar is at 50% and in the background you can see the square with the dotted lines. After some time the usual error appears