Oh boy, this Data Recovery job was something else. It was a Samsung S21 Ultra that had extreme water damage. Waaaaay beyond trying to repair it to get data...

➡Swipe through all the pictures to get an idea of what we were working with.

The only option here was a CPU Swap. If you saw my previous post, S21 models (and newer) have a "pin code IC" so to speak, that you must also transplant.

The problem is... on S21 series, this IC is inside the Samsung sandwich board. Which is a nightmare to split and even more difficult to reball.

My first step was to complete the CPU Swap to the donor board to make sure the phone can boot to begin with, which I was successful, but it wouldn't accept the correct pin code.

But at least I know the CPU and UFS are good and didn't die from all the water damage. And this confirms the donor is good & the parts I have are good.

Then I went for the split both donor & customer's board. I also made a video of this process on a previous post, so if you didn't see it, go check it out on my page.

Easily swapped the small 6 legged IC inside the sandwich, so I can get the pin code to work

Wicked both top & bottom layers

And attempted to reball the sandwich & this is where my troubles began. At first, we go No Power... WHOOPS

Checking on DCPS, I can see some heat on the side of the board.

I split the sandwich again & noticed some solder balls looked uneven. Maybe they bridged when I tried to sandwich. No shorts on top board & none detected on bottom board.

I tried re-squishing the sandwich without reballing and we got some life! BUT the image was all distorted. It was all static. I diode mode the connector & cross referenced ZXW and noticed some pins were reading as ground.

Those pins were not ground on the customer's board and of course, they go through the interposer.

So there I am, splitting this sandwich again.

I check those pads on the interposer & the short is gone. So it was definitely bridged.

I try to reball the sandwich again and viola! We got image, but charging was a little weird... then I see it's just bootlooping. It was only stuck at the first Samsung logo. I also noticed it would auto boot when plugging it into the charger. Samsungs do not auto boot, like iPhones.

So all this told me, there's still a problem somewhere.

I tried splitting AGAIN, and just re-squishing.
Same thing

Reflowed it and same results.

I went back and just decided to reball the "pin code IC" one more time, then wick the top & bottom boards again and try to reball again.

I do it.... and it doesn't charge. It doesn't even turn on my meter 😭
But it does boot with the power button, but once again, it's bootlooping.

SMH

So then I checked the board & noticed there's a gap in the sandwich. I rehot the sandwich & gently press down in hopes to connect the solder joints from the top & bottom board, but also have to pray that no bridges occur.

I do it. Visually, it looks like the gap is still there, but I can see solder joints stretching across the 2 sides & making connection.

I reassemble & plug in the charger... the meter lights up and the phone shows the lightning/charging symbol... then the temp warning. Of course, I didn't have the wireless charging coil plugged in. I plug it in & try again.... and we get the charging symbol.

AND it doesn't auto boot like before. This is an interesting change of events.
I use the power button to boot

It stays at Samsung logo for what feels like an eternity!

AND THEN WE GET THE LOCK SCREEN!

I type in the pin code.. BOOM! It unlocked

And here I am, typing out this story before I forget it all, while I download about 97GB of pics, videos, contacts, texts using CoolMuster.

YES, I know this was a long story, but here you are, reading it. So thanks for joining me in this journey, kind of, since you weren't really here.

How many Samsung sandwich boards have you reballed in your life?