Igor A. Melelekhine wrote:
You can upgrade SSD by yourself on M4 Mac Mini
Please be careful not to raise false expectations.
There is a teardown article on Reddit that claims that the flash chips in the M4 Mac mini are not soldered onto the motherboard, but are on a separate board. (I didn't know about development, and only searched for articles mentioning it because of your post – so thanks for the head-up.). However, as in the Mac Studio and desktop Mac Pro, this is probably a raw flash module – not a self-contained SSD.
There might be nobody other than Apple who carries compatible replacement modules, and presumably after you replaced the module, you would need the help of another Mac running Apple Configurator to get the M4 Mac mini and the new flash module "on the same cryptograhic page" so that you could re-install the operating system.
So don't order a M4 or M4 Pro Mac mini with less internal storage than you need, thinking you'll be able to easily add a cheap internal third-party M.2 NVMe SSD. Your practical options are still to order the Mac from Apple with the amount of internal storage you need, and/or to add external storage (from any number of third parties).
