Unreadable and unwritable tags?

Since I don’t want to play with breaking something I care about (or anything that isn’t mine), but I want to learn more about RFID stuff (not NFC), I got some cards and a reader off Amazon to play with at home.

Is there some unimplemented features with writing cards, or a guide on how to figure out what works? I got some T5577 chip keyring blanks that all the reviews claim works with nearly every card with the “copy guns” but when I’ve been making manual keyed test cards on the Flipper it seems like I can only write EM4100 and nothing else, I just get the “still trying make sure its writable” message.

Also, I found the “config card” that came with my USB reader doesn’t seem to read on the Flipper…not sure if there’s a way to get that added may benefit people playing with them? It just changes the output-format of the USB reader when tapped.

Read my last posts here :


So this also gets a bit more wild, I visited a friend this weekend who has one of the sketchy dedicated card clone machines and had some of the same looking fobs I have as well as full sized cards.

It seems like maybe the Flipper just really doesn’t like writing to the smaller fobs? Or maybe there is some trick to it? I also now got some T5577 credit-card-sized-blanks which work instantly write and read with every format the Flipper supports manual entering (I made one of each with like 1234567890 data as tests).

Once written, even the fobs I have trouble writing with the flipper in non-EM formats read just fine and work with other formats like HID and everything else we tried. Maybe its just poor coupling or I don’t know where to hold it right to optimally connect to the Flipper?

Amusingly, the ones in that particular eBay listing look exactly like the NFC-only fobs that we couldn’t figure out how to make write at all on anything so far. Yay china random things and random quality.

Small update - my friend just produced an old genuine 1st-party HID H10301 keychain fob from his old apartment and it took about 10 tries to make it read on the Flipper. Its probably 3/4" wide by 1.25 inch long.

Looks kinda like this one: Hager 150753 2-679-0023 HID PROXKEY 10 KEY FOBS - HID ProxKey II 10 Key Fobs

Maybe Flipper just really struggles with the smaller antenna fobs?