It seems when PICC_CMD_MFC_AUTH fails once on a 7byte Mifare Classic card, it's game over.
Subsequent PICC_CMD_MFC_AUTH attempts are always returning "63 00" code from the reader even when the correct keys are used.
4byte Mifare cards don't exhibit this behavior, it may be a bug in the actual ACR122U.
It seems when PICC_CMD_MFC_AUTH fails once on a 7byte Mifare Classic card, it's game over.
Subsequent PICC_CMD_MFC_AUTH attempts are always returning "63 00" code from the reader even when the correct keys are used.
4byte Mifare cards don't exhibit this behavior, it may be a bug in the actual ACR122U.