Magic card (UID-writable)
What it does
A magic card is a MIFARE Classic-compatible tag built to accept writes to block 0, the manufacturer block that normally holds a read-only UID on a real card. **Gen1a** cards need a special backdoor command sequence and only tools that support it can write them; **gen2** (CUID) cards accept a plain write like any other block, so any standard tool works. Either way, it is the blank a dump gets cloned onto when the UID itself needs to be reproduced.
Use cases
Write the target's UID onto block 0 to defeat a reader that authorizes on UID alone.
Write every recovered sector, not just the UID, to reproduce stored data and access rights.
Present a same-UID, different-data clone to see whether the reader checks anything beyond the UID.
How you use it
Confirm the card is gen1a or gen2 before you pick a tool, then write the dump:
pm3 --> hf 14a info # confirm it answers as a magic (gen1a/gen2) card
nfc-mfclassic W a blank.mfd dump.mfd # write the recovered dump, UID includedGen1a needs backdoor-aware tooling. A plain write against a gen1a card silently does nothing; the tool must issue the gen1a backdoor sequence first.
Some readers detect the mismatch. A magic card's ATQA/SAK can differ subtly from the original; a reader that checks those fields (not just the UID) can flag the clone.