I am trying to downgrade the ios version on C8500L-8S4X but failed
the current version is
C8500LR#show inv
NAME: "Chassis", DESCR: "Cisco C8500L-8S4X Chassis"
PID: C8500L-8S4X
C8500L#show ver Cisco IOS XE Software, Version 17.12.05a
ROM: 17.14(1r)
C8500L#DIR flash:
22 -rw- 752322985 Sep 23 2025 05:35:58 +00:00 c8000aep-universalk9.17.09.03a.SPA.bin
C8500L#show run
boot system flash bootflash:c8000aep-universalk9.17.09.03a.SPA.bin
Everytime failed when booting
[13:57:55:442]Package header rev 1 structure detected
[13:57:55:442]IsoSize = 752314202
[13:57:58:314]Performing Integrity Check ...
[13:58:02:913]Performing Signature Verification ...
[13:58:02:913]RSA Signed RELEASE Image Signature Verification Successful.
[13:58:03:367]
[13:58:03:526]%ERROR% Booting an incompatible image for this platform
[13:58:03:526]Failed to boot file bootflash:c8000aep-universalk9.17.09.03a.SPA.bin
[13:58:03:526]
[13:58:11:451]........
[13:58:11:451]autoboot: boot failed, restarting...
[13:58:11:451]
[13:58:11:451]Resetting .......
[13:58:11:451]
[13:58:11:451]
[13:58:20:903]
[13:58:20:903]Initializing Hardware ...
[13:58:51:355]
[13:58:51:355]Checking for PCIe device presence...done
[13:58:54:072]System integrity status: 0x610
[13:58:54:072]Rom image verified correctly
[13:58:54:072]
[13:58:54:072]
[13:58:54:072]System Bootstrap, Version 17.14(1r), RELEASE SOFTWARE
[13:58:54:232]Copyright (c) 1994-2023 by cisco Systems, Inc.
[13:58:54:232]
[13:58:54:232]
[13:58:54:232]Current image running: Boot ROM0
[13:58:54:232]
[13:58:54:232]Last reset cause: LocalSoft
[13:58:54:312]C8500L-8S4X platform with 15728640 Kbytes of main memory
[13:58:54:312]
[13:58:54:853]
[13:59:02:849]........
[13:59:05:578]no valid BOOT image found
[13:59:05:578]Final autoboot attempt from default boot device...
[13:59:05:647]Located 2025_08_26T10_14_45.655786.xml
[13:59:05:647]#
[13:59:05:647]
[13:59:05:706]Unsupported package header version (1635018067)
[13:59:05:802]Located harddisk_info_history
[13:59:05:802]#
[13:59:05:802]
[13:59:05:818]Unsupported package header version (1296244768)
[13:59:05:818]Located mode_event_log
[13:59:05:834]#
[13:59:05:834]
[13:59:05:881]Unsupported package header version (809120310)
[13:59:06:041]Located memleak.tcl
[13:59:06:041]##
[13:59:06:041]
[13:59:06:041]Unsupported package header version (540160049)
[13:59:06:041]Located ios_core.p7b
[13:59:06:041]#
[13:59:06:041]
[13:59:06:216]Unsupported package header version (53293069)
[13:59:06:216]Located trustidrootx3_ca_062035.ca
[13:59:06:216]#
[13:59:06:216]
[13:59:06:216]Unsupported package header version (1817785174)
[13:59:06:216]Located throughput_monitor_params
[13:59:06:232]#
[13:59:06:232]
[13:59:06:377]Unsupported package header version (1817785174)
[13:59:06:377]Located .iox_dir_list
[13:59:06:377]#
[13:59:06:377]
[13:59:06:377]Unsupported package header version (1769171759)
[13:59:06:598]Located c8000aes-mono-universalk9.17.12.05a.SPA.pkg
So I am wondering if the ios c8000aep-universalk9.17.09.03a is suitable
Thank you for you help
