So I used something like these some years ago to recover data off a phone, but I was wondering if the reverse is possible in having a bga soldered adapter with a microsd slot on top. Or if PCBs can even be soldered together like that. I've never actually checked if bga chips have raised pads or something. The purpose would be for rapidly testing custom firmware for shitty old devices that were designed to be replaced without removing the emmc to flash it separately.
TIL. Although to be fair, the removable part of that Orange Pi is a modular PCB that happens to have only an eMMC chip mounted on it. It's still very clever as it offers the user a choice in memory size, but it's apparently not standardized by any industry body, at least that I'm aware of.
Plus, if we allow that the loading if a normally embedded chip onto a PCB makes it removable, there's a Ship of Theseus quandary that arises lol