This anomaly applies to IC Rev. Engineering A, build codes QFAA-AA0, QFAA-AC0, CGAA-AA0.
Reading flash after an erase operation returns invalid values.
The flash page being read from was erased using NVMC.ERASEPAGE or NVMC.ERASEALL immediately before the read.
Verifying a flash region is erased may fail. Writing to a flash page will never fail.
Immediately after an erase operation, read from a page that was not erased in the operation, or write to any flash memory address. After one successful read or write, the symptom will not occur.
If ERASEALL was used, or it is not possible to identify which page was not erased in the operation, read from address 0x10000FFC after the erase operation as this is located in the FICR which is guaranteed to not be erased during the operation.