Is there any chance that an Ultralight EV1 chip could lose a write?
Is Read after write from Flash or RAM? (Ultralight EV1)
I have a situation where I use a CLRC663 with the C NFC Reader Library where my writes are not saved to the RFID Chip.
My sequence of operation is as follows:
In a single authenticated session
- Write to Page W [0x00112233]
- Write to Page X [0x00112233]
- Write to Page Y [0x00112233]
- Write to Page Z [0x00112233]
- Read 16 Bytes from Page W through Page Z
- Verify that Page W-Z as read matches the intended bytes written
- No mismatch, write verified and done
Then later when I read the chip, I find that one of the pages does not have the expected value ( I do not know if it is random, corrupted, or reverted)
I have this with about 0.1% of all my chips (among thousands)
Is it possible in theory that I am reading from the Ultralight EV1's RAM, but it is not fully committed to flash because of say... a weak NFC Field? Or am I guaranteed that all reads only read from committed flash?