I also have issues using SD cards with two Fairphone 4’s. I have tried
SanDisk Ultra 128 GB microSDHC Memory Card + SD Adapter with A1 App Performance Up to 120 MB/s, Class 10, U1 (Twin Pack). After seeing the initial prompts from Android about slow performance, I tried
SanDisk Extreme Pro 128GB microSDXC Memory Card 170MB/s Class 10, UHS-I, U3, V30
However, this seems to have made things worse, with 1 phone seeing the card is missing/corrupt and the other reporting errors using the cards. I have only just found these forum posts and the “recommendations” not to use SD Cards as internal storage, so I’d already done that. However, I’m somewhat bemused how Fairphone can sell a phone with an option which is so clearly inadvisable and not include something in the packaging as a warning if they’re not going to remove the option in the OS.
There seems to be mixed reports on Samsung cards working. Are there any confirmed reports of success with the Samsung Evo plus 128GB Micro SD SDXC Class 10 memory card U3 100MB/S (MB-MC128HA APC)? FYI I have raised case 485888 with Fairphone support. However, if I can fix it with a known working card rather than waiting for 5 days I would love to do that!
Thanks for your help.