I have a broken FP3 (most likely Power management chip is broken).
Could I rescue my data if I buy a working FP3 and just swap the memory/storage chiplet?
So I would dissolder the eMMC from both phones and solder the one with my data on the working phone.
Would the phone but afterwards? Gets data lost due to heating up during soldering?
This is going somewhat off-topic. But here’s how that usually works in pretty much all modern systems:
The whole memory/data partition gets encrypted with a randomly generated key. That key is then in turn encrypted using your unlocking code and stored in a specified location on that same memory.
So stuff is only freely readable if you don’t set an unlock code. If you set a code, you need to know it to decrypt. But if you change the code, only the key has to be re-encrypted, no your whole memory.
This is also how BitLocker, LUKS, self-encrypting SSDs, etc. do it.
This is going really off-topic and yes, details differ. Neither of us seems to know exactly how that might have been implemented for the FP3, however.
If anyone ever tries the transplantation, it’ll surely be interesting to know how it went!
In this specific case I’d probably still try to first use the oven method to manage a backup. Next in line would be the PM chip instead of the eMMC - assuming that if you have the means to transplant the eMMC, you should also be able to do this for the much simpler PM chip.