Macbook Air 2020 A2179 Internet Recovery and Battery Issues

[cheebster]

Hello, i have a batch of 10 Macbook Pros A2179 bought from a Costco return wholesaler.


The 10 of them show the exact same behavior;

They auto power on, to internet recovery spinning globe, fans to 100%.

Power consumption on USB-C port is 0.43a, shuts down as soon as unplugged. Battery doesn't charge at all. However, it boots to 20V on the Ampmeter.

Based on their iBridge versions (4.x and 5.x) these were shelfed for a long time.

All of them power on the same way; 100% fans, shut down as soon as they are unplugged. Removing the back cover shows the battery has 4.x volts directly on the + - solder blobs.

Internet recovery will not complete in any way, bought an official Apple USB Ethernet Adapter, stuck always at 24:00 and never progress on any of them. Battery is the issue i think

Impossible to boot from USB either, T2 machines and this disabled via T2 firmware by default.

So basically, i'd like to fix the battery issues ! 10 new batteries is 700$ down the drain.

What i'm wondering is; these batteires have firmware, i have seen MBRT the macbook repair tool which fixes the flag in the battery firmware to repair them. However, that's another 350$ again.

Is the firmware the issue or simply the batteries have drained ?

I have revived several batteries in the past using a DCPS on ipads, simply by 'jump' starting the batteries injecting 4.2v to them, and with good success, when ipads have been shelved for a long time.

If anyone can chime in on this, i'd be happy. Thanks ! Vincent

[cheebster]

Oh well, i've bought a new battery and tested it on 2 different units, exact same behavior, that means the battery isn't the issue. Anyone has a clue what could cause this on all of these units ? Thanks.. Vincent

[reformatt]

I did have an A2179 in recently with dead battery and screen which displayed similar problems. Sometimes it would boot to desktop, but most of the time it just hung on the Apple logo. I could get it into the bootpicker, but it would not go to recovery mode. I couldn't get it into DFU either via keyboard, which made me strongly suspect the keyboard. I got it into DFU via DFU Blaster running on another MAC, did the restore successfully. Still same issue, even with another known good battery.

My next step was to try this motherboard in a known good chassis, but didn't have one to hand at the time. I could not explain this behaviour, and I saw nothing on the board corrosion wise that led me to think it was the board. Customer decided to not proceed with the repair and that is where I stopped. So for me, eliminating the hardware in the rest of the chassis is the first step.

Fans running at 100% usually means missing sensor data. This can be from a lack of SMBUS data to the battery, as I've seen this occur on an A2338 when the battery flex cable was liquid damaged. This model uses a plug though, check the pins for damage etc and check values on the board for diode readings etc.

[cheebster]

Hello, ok, but dfu mode on t2 machines only restores the ibridge firmware not the os sadly.

I dont think its a hardware issue as i have 10 machines with the exact same issue. Called apple support today, senior tech had no idea how to fix this. Frustrating to say the least!

[kevingill]

Interesting that all 10 exhibit the same fault. I wonder if the environment has caused all 10 to fail, or just the amount of time stored? Have you left them on charge overnight to see if the battery voltage comes up? Do they go into DFU mode? They should at least boot to diagnostics or boot selection.

Also, are they iCloud locked?

[cheebster]

Hi there, they all come from the same source, which is a retail return pallet from costco. They were wiped of their original os that's for sure, and yes they are on an existing icloud account.

DFU mode works, ibridge os (t2 firmware) restores/revives successfully and they auto power on with 0.43a on internet recovery, they never charge, even tested with a new battery from mobilesentrix.

Thanks.. Vincent

[cheebster]

Anyone has a clue on this ? Thanks

[reformatt]

I'd start with transferring a board into a known working chassis, including known good battery. Where you source it is up to you, perhaps an iCloud locked one on eBay. Fan running flat out means sensor data is missing, so you need to establish whether this is a board or chassis issue. Another poster recently was thinking it was a board issue on a MAC, only to find it was the keyboard. Don't forget that the CPU is throttled to its slowest speed when fan is running full blast so this can have an impact on installing software.

Just my 2 cents. Take it or leave it.

[cheebster]

Hi there, thanks for the tips. I find it hard to believe i'm badlucked (or lucky enough) to have 10 units with the same exact issue, though..

[reformatt]

You don't know the history so you can't make assumptions. It could be whoever was testing these when they came back to the store was plugging in a faulty charger and zapping each one. Or it was the same owner who was doing something similar, and just kept exchanging them.

The way I would approach it is to halve the faultfinding by eliminating the board or chassis. Failing that, I would at least put a scope on the SMBUS data lines to the battery to see if there is activity, and that SYS_DETECT_L is indeed being pulled low by Q6955. Battery controller won't enable without that.

[cheebster]

AH! Fixed. It seems that i DFU Restored all the machines, but didn't DFU Revive which is different. Trying it gave a 4042 timeout error. So i went and used the new battery i ordered from mobilesentrix, and the same DFU Revive worked right away. Tried internet recovery, bingo! Restoring it right now and it's going.. Pretty happy, that's 10 machines saved from landfill

[kevingill]

Great news, So it was the batteries all along that caused the problem? Revive clearly was the way forward, but I presume with original batteries, even this method wouldn't work?