The issue we are encountering is as follows: When using a DESFire EV3 8K card, after sending the 0xFC format command to format the card, the card enters a "frozen" state and does not respond to any further commands. Even removing the card from the field, re-scanning it, or re-running the code does not resolve the problem. However, we found that when the card is read by a smartphone's NFC function, it recovers and can execute other commands normally. The problem reoccurs as soon as the card is formatted again.
Additionally, we tested several other DESFire cards. Three of the EV1 cards exhibited similar issues, while the three EV2 cards and two EV3 cards worked normally after formatting.
This situation suggests that after the card is formatted, it does not return to its normal operating state. However, when the card is read by a smartphone's NFC function, it seems to reactivate and return to normal operation. The strange thing is that only certain DESFire cards exhibit this behavior.
I'm having the same problem with EV3 cards after command 0xFC. I'm using a custom NFC reader with custom firmware. It works perfectly for all EV2/EV3 commands so far, except for this one.
Steps to reproduce:
Hello @Riowang-Akuvox
From your description, formatting failed. At PICC level, all applications and files are deleted by Format(0xFC) command,but before that, you must authenticate the card, and successed, and then you can format the application and files.
Hello @Riowang-Akuvox
As the final way, it is recommended to try the NXP Reader CLRD730 (PEGODA Contactless Smart Card Reader | NXP Semiconductors).