During my recent iPhone 12 CPU Swap Video (linked in the comments), I ended with the phone fully booting, but restarting every 3 minutes.

Since I didn't swap the NFC chips, I have to go through the "Swipe to Recover" screen, where it shows a white screen that says "Attempting Data Recovery".

I like to this of this process as it's "reprogramming the new NFC chips" so it can allow the phone to boot & unlock.

This process can take anywhere from 10-45 minutes, depending on how much data is on the phone.

In the video, when we started the "Swipe to Recover" process, I noticed that within 3 min or so, the phone would auto restart. So without the Swipe to Recover process completing, I am unable to access the data.

Due to how long the video was, I decided to end it there & post the fix here.

First thing I tried was a new charging port flex, as that's the most common fault of 3 min restart for iPhone 12, but no change.

I then decided to diode mode the charging port FPC connector, as that's where the sensor from the charing port flex (pressure sensor aka Prs0) would connect to, to reach the next part of the circuit.

And sure enough, I found a line that was OL, when it should have had a reading.

The line was labeled as "Eiger" (PPVAR_EIGER_S2_CONN) and I know I've seen a panic log that mentions Eiger, as being part of the charging port flex.

ZXW showed that there's a filter near the PMIC shield on that line.

Sure enough, the filter was missing. Most likely caused by my iron, when I was applying the low melt solder to the shield, as a way to make the shield removal easier.

I replaced the filter from the original customer's board & boom! The phone stopped rebooting & the data was saved!

It wasn't obvious that the filter was missing, as it was mostly covered in underfill too! So without measuring with my multimeter, I would have never found it.

Also, it's important to diagnose thing systematically. If you think through "what's the most likely cause of this?"

Then drill into that issue & confirm it's not it, then you move onto the next most likely, and so on.

This type of diagnosing, troubleshooting & fault finding skill comes from years of non stop working through these types of cases. We see so many different types of scenarios, that we can easily anticipate what could be happening, as we've probably seen something similar before.

I hope this post helps you see my thought process of how I help solve this case & successfully recover the customer's data.