PXR40RM Datasheet, PDF (299/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Boot Assist Module (BAM)
WARNING
If the shadow flash block is erased without reprogramming a new valid
password and censorship control word before a reset occurs it will contain
an illegal password and the debug port will be inaccessible. Also, if code
does not exist in the first bootable region of the internal flash to reprogram
the shadow flash with the proper censorship control word and password, the
device will be in a censored state and may no longer be usable.
4. Subsequent resets will clear the JTAG censor password register and the Nexus client TAP
controller will hold in reset again. Therefore, the tool must resend the JTAG serial password, as
described above, in order to enable the Nexus client TAP controller again.
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
9-19