Why am I getting downgrade disallowed here, I can understand why I wasn't allowed to flash up to PR_001, but now I'm flashing down from PR_235 to PR_280:

Jacks-rMBP:N9_Flash root# flasher -f -F 62A0A79D_DFL61_HARMATTAN_40.2012.21-3.280.04.1_PR_LEGACY_280_ARM_RM-696_PRD_signed.bin
flasher 3.12.1 (Oct 5 2011) Harmattan
WARNING: This tool is intended for professional use only. Using it may result
in permanently damaging your device or losing the warranty.

USB device found at bus 29, device address 6.
Device serial number is N/A
Found device RM-696, hardware revision 1603
NOLO version 2.3.6
Version of 'sw-release': DFL61_HARMATTAN_40.2012.21-3.235.1_PR_235
Sending ape-algo image (7103 kB)...
100% (7103 of 7103 kB, avg. 31018 kB/s)
Suitable USB interface (phonet) not found, waiting...
USB device found at bus 29, device address 6.
Device serial number is
Raw data transfer EP found at EP2.
Ping attempt 1 (250 ms)
Server application: 1.7.2
Found product RM-696 rev. 1603
Server implements softupd protocol version 1.8
Image SW version DFL61_HARMATTAN_40.2012.21-3.280.04.1_PR_280
Image moslo not present
Image mmc not present
Image tar skipped
Image config skipped

Battery level 50 %, continuing.

image [state progress transfer flash speed]
---------------------------------------------------------------------
[_] cert-sw [init 0 % 0 / 0 kB NA ]
[ ] cmt-2nd [pending 0 % 0 / 0 kB NA ]
[ ] cmt-algo [pending 0 % 0 / 0 kB NA ]
[ ] cmt-mcusw [pending 0 % 0 / 0 kB NA ]
[ ] xloader [pending 0 % 0 / 0 kB NA ]
[ ] secondary [pending 0 % 0 / 0 kB NA ]
[ ] kernel [pending 0 % 0 / 0 kB NA ]
[ ] rootfs [pending 0 % 0 / 0 kB NA ]
ERROR: SU_GET_UPDATE_STATUS_REQ terminated with error code 10: Security failure

image [state progress transfer flash speed]
---------------------------------------------------------------------
[f] cert-sw [init 0 % 1 / 1 kB NA ]
[ ] cmt-2nd [pending 0 % 0 / 0 kB NA ]
[ ] cmt-algo [pending 0 % 0 / 0 kB NA ]
[ ] cmt-mcusw [pending 0 % 0 / 0 kB NA ]
[ ] xloader [pending 0 % 0 / 0 kB NA ]
[ ] secondary [pending 0 % 0 / 0 kB NA ]
[ ] kernel [pending 0 % 0 / 0 kB NA ]
[ ] rootfs [pending 0 % 0 / 0 kB NA ]
Fetching error list:
========================================
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
bb5_rdc_cert_read failed
Downgrade disallowed (1342066089)
[Pipe 0] Finishing in error state with status 10
========================================

ERROR: Failed to flash images