A1707 critical update

[hgoncalves]

Hi,

I've an A1707 that is always asking for a critical update, even when installing a new macOS.

The disk is reconized in restore mode, it has Monterey instaled, and already run first aid with no errors.

Should I start with a DFU restore?

Don't know where to start.

Can you help?

 

[2informaticos]

DFU for A1707?

The update is required by touchbar.
Can't install it?

 

[hgoncalves]

Sorry, din't think it well about DFU...

The install always fail, and I'm stuck in this screen (loop)

 

[2informaticos]

Then check all about touchbar problems.
We have many threads and information on the forum.

 

[hgoncalves]

Hi,

Following Luke's post, I found that with the touchbar disconected, and in safe mode, I was able to install Big Sur, and now the mac boots in safe mode, and so, I supose that the problem is on the touchbar (not sure)

Shoul I replace U3900? Is there any way to phisical disable touchbar?

 

[2informaticos]

Any history available?

Did you check any signals and voltages on touchbaar connectors?

 

[hgoncalves]

Hi.

Client said that one morning this error appeared.

J4401 voltages:
PIN 3 = 0.450V
PIN 5 = 0.355V
PIN 9 = 0.402V
PIN 11 = 0.417V
PIN 15 = 1.8V
PIN 17 = 1.8V
PIN 21 = 1.8V
PIN 23 = 1.8V
PIN 4 = 0.330V
PIN 6 = 0.360V
PIN 10 = 0.062V
PIN 12 = 0V
PIN 18 = 3.3V
PIN 20 = 3.3V
PIN 22 = 3.3V

J4402 voltages (with J4401 cable conected):
PIN 1 = 0V
PIN 3 = 0.224V
PIN 7 = 0.324V
PIN 9 = 0V
PIN 13 = 1.790V
PIN 15 = 0V
PIN 19 = 0.520V
PIN 21 = 1.8V
PIN 2 = 0V
PIN 4 = 0.460V
PIN 8 = 1.8V
PIN 10 = 0V
PIN 14 = 1.8V
PIN 16 = 1.8V
PIN 18 = 1.8V
PIN 20 = 1.8V
PIN 22 = 5V

 

[2informaticos]

You must check with both cables connected.

I recommend you to test the machine with known good touchbar.

 

[hgoncalves]

Hi.

Testing with a known good touch bar I have the same result.

Critical update needed.

 

[2informaticos]

Doesn't even start touchbar installation process?
The above readings taken with both J4401/2 connected?

 

[hgoncalves]

Hi,

No it doesn't start. It asks for the wifi password, and then just shows an error, saying that it need to instal critical update, but taht an error ocurred.

Sorry about my question, but how can I measure then with both J4401/2 cables connected?

 

[2informaticos]

Find proper test points, using boardview.
You may need to work with board on the desk, connecting a (known good) spare touchbar.