Chosen Solution
In step 12 of the teardown Samsung Galaxy S9+ Teardown we can see the Toshiba THGAF4G9N4LBAIR 64 GB UFS (NAND flash + controller) . Can we replace it with a 128GB Flash integrated circuit? It is a BGA chip that should easily come off and it can be replaced with a pin compatible 128GB flash chip such as https://ro.mouser.com/ProductDetail/Tosh… How much will it cost?
You may need to format the NAND, that would require a specialized tool, however I don’t think you need to for a Samsung device. The challenge would be sourcing the alternative NAND, however, if you are able to, theoretically, you could swap it, then flash it through ODIN, and you should be good to go.
