Apple configurator 2 error

[huzeafa]

Good day guys

have got an A1989 with the following error message when I try to restore it in DFU MODE.

THE SYSTEM CANNOT BE RESTORED ON THIS DEVICE. GAVE UP WAITING FOR DEVICE TO TRANSITION FROM DFU STATE TO DFU STATE,

Please note that the board is stuck on 5V, with no liquid damage, that's why am trying to restore it.

I would also like to know if the issue is other than the T2 chip, will I be able to get the device into DFU MODE at all ? I mean if for example, there is an issue with one or more of the CD32, will I still be able to get the device into DFU MODE?

 

[2informaticos]

DFU mode do not switch from input 5V.
CD3215 chips require good communication with T2, which can fails at that moment.

But T2 requires an SSD in working state, as it has a dedicated partition there.
You can have T2, or SSD problem now.

 

[huzeafa]

Am sorry, but am lost, so does this mean my CD3215s are working? I only have to worry about either the T2 or SSD?





SOMETHING ELSE PLEASE: please do help me correct my understanding of fan issues, ((( when I start up the machine and the fan immediately becomes loud I attribute this to a fan circuitry issue, however when I start the machine and the fan spins really loud after a brief delay I refer to this as a sensor issue, please is this correct?

 

[2informaticos]

For DFU mode, CD3215 are not required to switch to 20V.
R2 firmware corruption can prevent a correct communication.
So T2 must be able to be restored with 5V only.
If T2 has an internal damage, or it can't get access to its partition on SSD, DFU can't be completed.

Fan starting with full speed can also mean the board started in SMC bypas mode.
This can happen when power button is affected by corrosion and ONOFF signal drops into low level, but not shorted to ground.

 

[Gurmon]

If seen a lot of this in the past few weeks. wasted countless hours experimenting swapping parts from known good boards. (CD32s)

A lot of the time a see cycling at PMU_SYS_ALIVE @ 0.4V 1.2hz following the start-up sequence. At this point I put these all down to failure of T2 chip.

 

[huzeafa]

thank you for your time, on the current machine I have at hand for the T2 error, what else can I do?

 

[huzeafa]

@Gurmon, what else can I do?

 

[Gurmon]

First thing is to measure all the LDO's from the CD32s. Make sure none are missing. Also measure in diode mode of all LDO lines (power off) of CD32s. check if there is no odd readings.

Then follow the start-up sequence to ascertain how far the board boots. This is good to understand how these boards work.

If you cant get the firmware on there, the board is scrap. My repair rate of this stuff is down to about 40% and heading downwards. A small amount of liquid firmly kills these boards for good.

 

[huzeafa]

@Gurmon thank you

 

[2informaticos]

If you get all AWAKE and SLPS2R voltages, T2 doesn't need to talk with CD3215 chips.
In fact T2 firmware corruption will prevent correct communication.
DFU is needed to solve such kind of problem.