How do I remove read only mode from NFC tag

Question

I am using NTAG203 NFC tags. I made it read only mode by mistake. How can I change read only mode to writable mode?

Answer 1

That depends on how you made the tag read-only:

• The tag has the capability to permanently write-protect its memory using lock bits. Once these lock bits are programmed, its impossible to revert those memory areas to a writable state.

• The tag, when used as an NFC Forum Type 2 tag containing NDEF data, has an additional read-only indicator in the NFC Forum tag's capability container. If only that indicator was used to set the tag to read-only (and no lock bits were set), you could still change the content of the tag. While you cannot reverse the read-only indication in the capability container to indicate read/write access, you could use low-level write operations to access the data pages (pages 4 to 39) of your tag. (E.g. on Android you could use the writePage() method of the MifareUltalight object.)