- * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
- * %0xFF bytes
- * UBI_IO_PEB_FREE: the physical eraseblock is free, i.e. it contains only a
- * valid erase counter header, and the rest are %0xFF bytes
+ * UBI_IO_FF: the read region of flash contains only 0xFFs
+ * UBI_IO_FF_BITFLIPS: the same as %UBI_IO_FF, but also also there was a data
+ * integrity error reported by the MTD driver
+ * (uncorrectable ECC error in case of NAND)