Desoldering chips isn't likely going to work. That has the presumption that the T2 doesn't have an anti-tamper mechanism built in and that the desoldering process won't modify any data. FileVault on or off, the data is always encrypted on the T2 drive. What FileVault does is put another encryption key around the key used to encrypt the drive. If there is no "wrapper" key, then the T2 just decrypts on demand, but the data at rest is always encrypted using the key the T2 has. ...iFixit just posted their 2018 MacBook Air teardown. Important (to me, at least) points:
- I didn't notice any secret diagnostic port for the storage (as with the iMac Pro - this may be a "feature" of using the T2 for the SSD controller). If the computer gets so messed up that you can't even use Target Disk mode, there won't be any mechanism (short of de-soldering the flash chips and the T2 and somehow getting them to work together on a new board) for extracting your files. This means backups (which are always very important) become extra important, since you can pretty much forget data recovery. Hopefully, it also means that any damage severe enough to prevent normal access will also make chip-level access impossible (because of a damaged T2 losing the encryption keys), so dumpster divers won't be able to get your files after you've given up. Of course, using FileVault in addition to the T2's encryption can protect against this if this "hopeful" guess turns out to be wrong.