A1707 820-00928 critical Update failure

[Fizzl92]

This A1707 was waterdamaged. I fixed all the waterdamage and it turns on again. I noticed two things:

- it needs ~ 40 sec. until it shows anything but fans spin from the second i press the power button.
- after a long boot time i get the same error as shown in the post on this forum (after choosing a network).

https://www.jamf.com/jamf-nation/discussions/22727/critical-update-won-t-install-after-imaging

I run diagnostic by holding D key at start and it shows no errors. I tryed to reinstall, boot from an external drive... - no change.
I disconnected the tuochbar (this may have nothing to do with the error but i read that this update should be a update for the touchbar itshelf), formatted the drive, reinstalled and did not connrct it the the internet and i can boot up one time. after restarting i get always the same error. I tryed a lot of other suggestins from the web but still no change. So i am stuck.

 

[ALB-Repairs]

`im fairly certain this will have something to do with a damaged touchbar controller but i havent got any further than that myself.

 

[bjf]

This has always been triggered by an SSD issue for me. Do you have the J9600 lifeboat connector attached? This is usually one of three things: either the connector isn't on, the lifeboat is damaged, or there's an issue with the SSD. It also seems to have something to do with the battery. I've had this happen sometimes until I have everything back together. Make sure everything is plugged in, including a good battery. And make sure it's charged at 30%. The fans spinning up might be a different unrelated problem.

 

[Fizzl92]

This is starting to suck. I checked the liveboat and it looks perfektly fine. I reattached it and still the same error. I also noticed that it has no sound (no chime - even after PRAM Reset). And it boots fine into secure boot mode so i guess that the SSD should be fine?! Also first Aid shows no errors if i check and whipe the SSD with my USB drive. Battery works fine and lasts long (actually >90% charged) Same error without Battery plugged in...

 

[ALB-Repairs]

This is starting to suck. I checked the liveboat and it looks perfektly fine. I reattached it and still the same error. I also noticed that it has no sound (no chime - even after PRAM Reset). And it boots fine into secure boot mode so i guess that the SSD should be fine?! Also first Aid shows no errors if i check and whipe the SSD with my USB drive. Battery works fine and lasts long (actually >90% charged) Same error without Battery plugged in...

i Wonder if it has anything to do with apple trying to nerf independent repair (news thats going around today)? I had one of these machines working in OSX after a repair, the next reboot it had 'critical update missing'

 

[Fizzl92]

Thank you for the answers. I did more research and it is 99% an error with U3900 (touchbar controller). So i measured the resistance from all pins on both connectors (in diode mode) compared these to a working one and there is no broken link or short but the reset for the display and 4 data lines read 0.2V higher. Also this reset (pin 12 J4401 and DFR_DISP_RST_L) are low so i guess it want to deactivate the Touchbar as there is just U3900 on this line.
So i am thinking to give in and give it what it want. This brings my next question up:
Is there a way to deactivate the touchbar manually (forever)?? Like take one or all powerinputs away from U3900 or remove it completely?
On top of this i am not even sure if that update is really for the Touchbar and/or if it wont try to install this update if there is no touchbar...(as it is also trying to install it even if i dont plug both connectors in)...
Actually i am trying to get it to run windows as a "last chance" but even this is nearly impossible on a device like this...

 

[ALB-Repairs]

Just an update.
The one that randomly hit me with this message was for a battery not being plugged in. It may be a case when it recognizes some missing hardware that it throws this error. I was confident in U3900 failing on the other one i had though.