820-01521: Won't all install of OS. High Fan as well

[macRepairAmb]

Have this MacBook air 2018 version with T2 chip that was sent in due to not being able to load OS. It powers on to question mark folder. When i attempt the recovery process, the progress bar for the internet download starts to jump about. Also, the fan is running very high after about a minuter or 3 of the unit being powered on.

AHT result says there's an issue with the SMC, suspecting either due to the high fan reading or the smc itself. Any suggestions as to where to start on this one.

 

[2informaticos]

Did you try DFU recover?
Can be other T2 firmware issue...

 

[macRepairAmb]

I tried the DFU restore and got the below error,

Gave up waiting for device to transition from DFU state to DFU state. [com.apple.MobileDevice.MobileRestore – 0xFA5 (4005)]

 

[2informaticos]

Did you read all the information about DFU recover process?
There are some refferences about incompatible cables.

 

[macRepairAmb]

Yeah, i used the apple USB-C to USB-C laptop charger cable and not a knock off version. I also tried the iPad pro usb-c to usb-c cables as well with the same result

 

[2informaticos]

I think someone reported problems with original Apple cables.
He did the job with some compatible cable...

Can be other thing than T2 firmware in your case, but should discard it first.

 

[macRepairAmb]

Getting the same error with another no apple cable.

Have you ever replaced the SMC chip on a board with T2 chip and was successful?

 

[2informaticos]

SMC functions are included in T2...

 

[macRepairAmb]

So symptoms i just observed:
Battery isn't charging or booting from it.
Not recognizing bootable usb for OS install but will recognize external HDD
Even though it recognizes external HDD, it will never boot into the HDD but ends up going into internet recovery which never finishes the load process.