820-00281 internal SSD issue

[tcampbell34]

Hello. I got a 820-00281 board in that is not liquid damaged and the board is very clean, but I cannot get it to boot to the internal SSD. When I first start the computer, it does give me an apple logo and the progress bar starts and goes maybe about half way before it reboots itself and gives me a kernel panic error. If I hold the option key on boot, I can see the internal SSD come up as an option to boot from. I was able to boot into recovery mode but the internal SSD does not show up in disk utility. I checked the board and found that PP3V3_SSD_NAND is 3.3v for the first couple of seconds after I connect the charger, but then it drops to 0 and does not come back. I checked U9390 and SSD_PWRCON3 fluctuates between 1-1.8v in the first few seconds the board is powered, and then that also drops to 0. I see that signal comes from U8605 so wondering if that chip is the issue or could there be some other reason for this?

 

[2informaticos]

Be sure metal plate of Lifeboat connector is correctly fixed in place.
Remove it, clean and put back.

 

[tcampbell34]

It is correctly in place and it is spotless. I took it off and cleaned it anyway and put it back but same result.

 

[2informaticos]

Internal SSD appears always on the boot menu?
Is still there if you wait few minutes in boot menu?
Also try starting from USB macOS.

 

[tcampbell34]

Yes the internal SSD always appears in the boot menu when I hold the option key and it does not go away. I waited about 10 minutes and the internal SSD was still visible and I was able to select it to boot from but it kernel panics. When I try to boot from my USB macOS, it kernel panics most of the time but some times it will make it to the critical software update screen, but fail to download it.

 

[2informaticos]

Follow the steps recommended by dulefawks for critical update error.
Try to to discard any relation with your case.
Disconnect internal LCD assembly and test with HDMI monitor.

 

[tcampbell34]

Ok. I followed his instructions and disconnected the touchbar, LCD and touchID button but still cannot boot to USB macOS. It boots to critical software update each time. I tried to install the update using the internal Wifi and also by plugging in my phone and using my LTE connection but it fails both ways. Seems to be because it cannot save the update to the internal drive.

 

[2informaticos]

Disconnect only LCD assembly, keep al other things connected.

Should be good to try known good working BIOS, clean ME too.

 

[tcampbell34]

Tried only disconnecting the LCD and still have the same issue. I tried a know good BIOS file with a clean ME also and still the same.

 

[2informaticos]

Can you boot Linux live, or Windows tjhrough USB?

 

[tcampbell34]

Yes I was able to boot into Linux Mint on this computer and I can see the internal drive in Linux.

 

[2informaticos]

Try to run some SSD test under Linux.
Even just erase and copy some files on it.

 

[2informaticos]

I just remembered one dukefawks post:
"Boot from wifi, hold shift+command+alt+R and turn on machine.
It should boot to the installer from the original OS that was shipped with the machine.
Can it still not see the SSD?
If not open up terminal and at the prompt type:
diskutil eraseDisk JHFS+ SSD disk0"
See if applies in your case...

 

[tcampbell34]

I was running some tests on the SSD in Linux but I realized that after a few minutes, the drive also disappears from the list of available disks. Most of the tests I ran failed to complete, but one did complete and said basically the entire drive was all bad sectors. Drive does not show up when booting into internet recovery and that command you gave me gives me an error “failed to unmount disk”. The drive is probably dead so this is probably a waste of time. Thanks for the help.

 

[2informaticos]

This should be some dead NAND chip.
You can try a reflow at least, before trash the board.

 

[overshoot]

I have the exact same issue on same board model. There was a bit of corrosion on the edge but the components impacted have no interaction with the SSD.
Same thing I can sometimes boot to internal drive and after a few minutes, the MacBook will restart. Then, at boot menu, internal won't show up.
At this point, if I try to boot up from an external drive, I will be getting the "critical software error" which is normal since the internal drive is not detected and is needed for BridgeOS (as Dukefawks mentionned in another post).

Can we swap the NANDs or only reflow them?

 

[2informaticos]

Start with reflow.
If you replace a NAND chip, the information required by system will be also lost.

 

[overshoot]

These are under-filled chips. 4 of them + controller.
how do you recommend reflowing such chips?

I've just tried with the Apple recovery tool and I am getting read/write errors using software like DriveDX.

 

[2informaticos]

Reflow just for test supposed internal chip issue; not melting balls...

 

[ZAKLINTOWN]

Sorry for silly question as obviously different air stations different temperatures however what would be good T to re-heat internal of the chip without messing up solder balls under the chip(specifically under filled chips)? From experience too hot pushed solder balls out and messed up the whole thing...