M1 A2337 Not able to access Recovery or DFU mode

[rodgsilva]

Hello everyone,
I have this machine here that was bought as "scrap for parts" badly damaged and ripped display.

The machine gets 20v, chime and can boot to the login screen when attached to an external monitor. however even with the password and yes I have access to the original owner says "Your Account is locked".

The issue is that I can't access Recovery or DFU mode, the power button work for turn the machine ON so I guess it's not faulty.

After some further investigation I found that there is damage some damage on the logic board it self.

I'm missing a couple capacitors (C8462 C8463) and ripped pads on the PPVDD_SOC_S1 rail.
- Board 820-02016

For someone with more experience, could this be the cause for not being able to perform any of the Start up commands, or not?
There is any other way to force such modes?

I'm just a repair enthusiast and for me this board is just a fun learning experience so I would be not afraid to go on with the soldering station but I would need to find these parts first.

Thanks for your time.

[rodgsilva]

Re: M1 A2337 Not able to access Recovery or DFU mode

I was able to find more info about forcing DFU.
Not sure if I can share links here's so I'll just reference from Logi.Wiki

"100% direct DFU mode using jumper
* locate FORCE_DFU jumper. on some Macbook Air boards there is just a testpoint which needs a wire to connect it with 1.8V. This signal needs to be pulled up to 1.8v to activate FORCE_DFU
* power-reset the device (unplug the battery, plug it back).
* Pull FORCE_DFU to 1.8v line
connect DFU cable to the device. It will both activate and autostart the macbook which will act as a proper "power button" trigger, switching the device straight into DFU.

This results DFU mode in 10/10 cases unless there is something wrong with T2/Jumper/CD321*/Cable"

For the A2337 there are just solder points so can be done with tweezers or soldering a jumper.


I was able to enter DFU and revive the machine, now just waiting on the previous owner to create a Backup before full restore.

I've also noticed that the iPhone 6 board has some of the 0201 missing caps so I should be able to grab from a dead board that I have.

However I still have more damage on the Logic Board on PP2V5_AWAKE_NAND.
L7760 is damaged and I'm not able to find a replacement for this inductor (0.47UH-20%-6.9A-0.022OHM PIUA25201B-SM) so if anyone have information about a possible similar replacement or a donor from where I can grab I would appreciate.

[rodgsilva]

MBA A2337 820_02016 board working but missing components (beginner question)

Hello, I have this M1 A2337 board here that I already did a post on:
(https://www.badcaps.net/forum/showthread.php?t=116553)

After I was able to force DFU and did a restore with Apple Configurator2, only today I got back from the previous owner who did the process to remove activation lock remotely, so I was finally able to activate and reinstall the OS.

I put in another chassis and seems to be working fine (apart from the original issue with not being able to access startup options or DFU mode using the power button).

But I'm still missing some components near the CPU area and I would like some help from more experienced people determining "how important" they are.

The parts missing are from PP2V5_AWAKE_NAND
L7760, C779M and C779N


apart from that I'm still also missing two caps C8463, C8462 on PPVDD_SOC_S1

For the caps would not be too hard to find replacements but I'm having trouble with that inductor. (maybe I'm just not searching correctly but with the data on the schematic I can't see to find anywhere)

I would not thrust this board with any important data anyway due to the state I got it but I would appreciate some advice in what would be the best thing to do.

Thanks for your time

[Sniffy]

Re: M1 A2337 Not able to access Recovery or DFU mode

I was able to find more info about forcing DFU.
Not sure if I can share links here's so I'll just reference from Logi.Wiki

"100% direct DFU mode using jumper
* locate FORCE_DFU jumper. on some Macbook Air boards there is just a testpoint which needs a wire to connect it with 1.8V. This signal needs to be pulled up to 1.8v to activate FORCE_DFU
* power-reset the device (unplug the battery, plug it back).
* Pull FORCE_DFU to 1.8v line
connect DFU cable to the device. It will both activate and autostart the macbook which will act as a proper "power button" trigger, switching the device straight into DFU.

This results DFU mode in 10/10 cases unless there is something wrong with T2/Jumper/CD321*/Cable"

For the A2337 there are just solder points so can be done with tweezers or soldering a jumper.


I was able to enter DFU and revive the machine, now just waiting on the previous owner to create a Backup before full restore.

Reading the schematic, it seems like SOC_FORCE_DFU is pulled up to 1.25V via a 1kOhm resistor in the schematic/boardview (clipped to the imgur link below), rather than pulling straight to 1.8V... but I really don't know.

imgur OZmQL9t



The issue might be that I don't have a keyboard/screen/touchID/battery/IO board connected aside from a usb charger or DFU cable.

Board boots fine straight to recovery after nand swap, but it doesn't see any volumes at all (idk if that's because I disconnected touchID, but at the bare minimum, the firmware needs to be updated since I swapped to kioxia nand)

With the 1kohm up to 1.25V, the board just boots to recovery, and PPVBAT_AON_CONN is at 12V. With a deadshort from SOC_FORCE_DFU to PMU_ONOFF_L, the voltage drops from 1.8V to 1.4V, but I chickened out and disconnected USB-c power after I saw PPVBAT_AON_CONN go negative. (board still boots to recovery fine).

It turns out I need a newer version of apple configurator 2 to detect m1 boards anyways though, so maybe SOC_FORCE_DFU shorting to PPVBAT_AON_CONN worked and I just didn't give it a chance?

Thanks in advance. I'll grab my board and check for those components you are missing... though there are plenty not populated on my board too and the schematic does call out a bunch of things to not be connected/populated.

[rodgsilva]

Re: M1 A2337 Not able to access Recovery or DFU mode

Reading the schematic, it seems like SOC_FORCE_DFU is pulled up to 1.25V via a 1kOhm resistor in the schematic/boardview (clipped to the imgur link below), rather than pulling straight to 1.8V... but I really don't know.

imgur OZmQL9t



The issue might be that I don't have a keyboard/screen/touchID/battery/IO board connected aside from a usb charger or DFU cable.

Board boots fine straight to recovery after nand swap, but it doesn't see any volumes at all (idk if that's because I disconnected touchID, but at the bare minimum, the firmware needs to be updated since I swapped to kioxia nand)

With the 1kohm up to 1.25V, the board just boots to recovery, and PPVBAT_AON_CONN is at 12V. With a deadshort from SOC_FORCE_DFU to PMU_ONOFF_L, the voltage drops from 1.8V to 1.4V, but I chickened out and disconnected USB-c power after I saw PPVBAT_AON_CONN go negative. (board still boots to recovery fine).

It turns out I need a newer version of apple configurator 2 to detect m1 boards anyways though, so maybe SOC_FORCE_DFU shorting to PPVBAT_AON_CONN worked and I just didn't give it a chance?

Thanks in advance. I'll grab my board and check for those components you are missing... though there are plenty not populated on my board too and the schematic does call out a bunch of things to not be connected/populated.

Well I wish I could help but I'm a total beginner and I just followed the steps from the wiki, and worked fine. I don't remember if I tried with the board lose or if was already in the enclosure with all the IO, but the battery was not connected for sure.

----------->

I also just coming back to report that I found a donor in perfect condition but with activation lock, so I pulled the missing parts from...

Had to run some wires to repair broken traces and missing pads, the job end up looking pretty ugly overall, but all lines had correct resistance and continuity.

I also got say I almost had a heart attack when I plugged the charger and got stuck at 5v 200mha, not sure why but luckily it turned ON and it's working fine after I put the heatsink and did the full reassembly.

In the end I didn't notice any change at all, and original issue still persists:
I can't access Recovery mode, when I'm holding the power button the machine just keeps rebooting.

I'll be testing for a while but so far so good.

[Sniffy]

Re: M1 A2337 Not able to access Recovery or DFU mode

Well I wish I could help but I'm a total beginner and I just followed the steps from the wiki, and worked fine. I don't remember if I tried with the board lose or if was already in the enclosure with all the IO, but the battery was not connected for sure.

----------->

I also just coming back to report that I found a donor in perfect condition but with activation lock, so I pulled the missing parts from...

Had to run some wires to repair broken traces and missing pads, the job end up looking pretty ugly overall, but all lines had correct resistance and continuity.

I also got say I almost had a heart attack when I plugged the charger and got stuck at 5v 200mha, not sure why but luckily it turned ON and it's working fine after I put the heatsink and did the full reassembly.

In the end I didn't notice any change at all, and original issue still persists:
I can't access Recovery mode, when I'm holding the power button the machine just keeps rebooting.

I'll be testing for a while but so far so good.

Hm, ok that's interesting. So DFU recovery worked in the sense that you did a complete restore? or you didn't erase/restore it?

There should be both recovery and fallback recovery after you reinstalled I think (2019 copyright vs 2021 copyright in the about menu), but if the recovery volume is missing then you wouldn't be able to boot to it (not sure about internet recovery though).

I need to see if I can get a low-health battery cheap locally if that might be the issue... the one that came in the laptop is currently sitting in a bucket of saltwater lol.

[rodgsilva]

Re: M1 A2337 Not able to access Recovery or DFU mode

Hm, ok that's interesting. So DFU recovery worked in the sense that you did a complete restore? or you didn't erase/restore it?

Since I was not sure if there was still any important data on the machine I Just did the "Revive"
Once the progress finished the mac would boot directedly to the Activation step.
Stayed that way for a month when I finally got back from the previous owner and we did the process to remove from his iCloud.