820-3437-B Not detecting MacOS (weird)

[PhilipC]

Have an 820-3437-B here that does not want to boot into MacOS (Flashing folder). So I tried booting into Mojave through USB and still flashes as well but boots into Sierra via USB but the thing is, it also does not want to boot into Sierra via SSD directly (flashing folder). Was liquid damaged but was cleaned (ultrasonic). Tried working SSDs, even installed Sierra on the same model MacBook Air and swapped the SSDs around.

 

[2informaticos]

Check solders and traces for J3700.
UC doesn't rebuild corroded traces.
Post U3740 voltages, with SSD inserted.

 

[PhilipC]

Check solders and traces for J3700.
UC doesn't rebuild corroded traces.
Post U3740 voltages, with SSD inserted.

J3700 looks good.
U3740
pin 1 = 3.42v
pin 2 = 1v
pin 3 = 3.3v
pin 4 = 3.42v
pin 6 = 3.24v
pin 7 = 0
pin 8 = 0

Forgot to mention that it does detect the SSD via MacOS but does not detect the OS installed just flashing folder. What's even weirder is that the board number is 820-3437-B but the serial number says that it's an Early 2014 Air 13" model and I have the same working board but other one says Mid-2013.

There was only corrosion around backlight area and Jtag (removed now)

 

[jadao]

Air 13?? 820-3437-B can be mid-2013 or early 2014 no issue there.
Air 13?? 820-00165 start at 2015, 2016, 2017, don?t know for later.

For Os not detected are you sure it?s not an EFI update / new Apfs file system issue?

If not sure about it, you may try a clean install from internet with HFS+ journaled formatted ssd just to eliminate any doubt.

 

[PhilipC]

For Os not detected are you sure it?s not an EFI update / new Apfs file system issue?

If not sure about it, you may try a clean install from internet with HFS+ journaled formatted ssd just to eliminate any doubt.

Unfortunately, I already looked at APFS to see if it's the issue and yes I tried HFS+ journaled and still flashing folder although I could boot into Sierra HFS+ via USB but not Mojave APFS via USB.

 

[brunomotter]

Try making a bootable USB installer with High Sierra on it and make a clean install erasing all partitions and formatting as HFS+ first. Then try installing a whole new copy of MacOS in the HFS+ partition... The EFI will be updated and probably things will work again!

 

[PhilipC]

brunomotter commented
1 hour ago
Try making a bootable USB installer with High Sierra on it and make a clean install erasing all partitions and formatting as HFS+ first. Then try installing a whole new copy of MacOS in the HFS+ partition... The EFI will be updated and probably things will work again!

I just did that and still remains the same still flashing. Tried different formats. Already formatted the SSD, deleted volume, created a new partition. Ran out of ideas on what to do. The only way that this MacBook is usable is to use a bootable USB drive. Tried Internet recovery and same problem.

 

[2informaticos]

U3740 voltages are good.
You should have some corroded trace, or component; classic issue for liquid spill...