820-3332-A Screen stuck on boot apple logo

[BCN_Techs]

The customer tried to change the battery and after that, it stays at the logo.

I have tried to boot from an external hard drive/pendrive and they never fully load.

Any suggestion?

 

[2informaticos]

Did you connect back original battery?
At least try disconnecting new battery; chinese crap may cause weird issues.

Did you resolder U8900?
You can also try disabling GPU, just in case; easy to do on this model.

 

[BCN_Techs]

Yes, I tried with an original battery but it does the same thing.

Instead of resoldering it, I changed it.
I haven't tried disabling the gpu.

 

[2informaticos]

Run corresponding ASD; OS version can test GPU.

 

[BCN_Techs]

I have disabled the GPU and now it starts OK: GPU is damaged?

 

[2informaticos]

I don't see other reason...