This technical support bulletin (TSB) has been published to advise Juniper customers on the Junos Software Release support for EX4500 with new USB 2.0 controller with Revision number 11 or higher. This TSB also outlines Junos support for EX 4500 (rev 11 and later) and a version "check" that was introduced part of Junos to prevent downgrading Junos Software Release to an incompatible release.
Junos Release Versions Supported for EX4500 Hardware revision 11.xx, and later, with new USB 2.0 controller Juniper is shipping EX4500 with new USB2.0 controller hardware recently .These EX4500s with new USB 2.0 controller ((hardware revision 11.xx, and later) are only supported on the Junos releases listed below. If you force to downgrade an EX4500 with hardware revision “11.xx” or above on non supported release it might fail the downgrade and may get stuck during the boot process. Supported Releases: 10.4R14 and above 11.4R8 and above 12.1R6 and above 12.2R4 and above 12.3R3 and above All later Junos releases Junos Hardware Check implementation - Verify Hardware and Junos Support: With supported Junos releases a hardware check was introduced to prevent the unit from being downgraded to a JUNOS release that does not support this EX4500 hardware revision “11.xx”. If you are running one of the releases below and attempt to downgrade to a release that is not on the “JUNOS Release Versions Supported for EX4500 Hardware with new USB Controller mentioned above, then it will prevent the downgrade and post a message. The following message will be displayed if you try to downgrade to a release with the requirements mentioned in the "JUNOS Hardware Check" section. fpc0: WARNING: Upgrading/downgrading to a release that does not provide WARNING: support to the new hardware in the platform WARNING: The supported releases for this platform are WARNING: 10.4R14 and future releases WARNING: 11.4R8 and future releases WARNING: 12.1R6 and future releases WARNING: 12.2R4 and future releases WARNING: 12.3R3 releases and all future releases Refer PR1023394.
OUTPUT 1: Command: show chassis hardware extensive root@EX4500> show chassis hardware extensive Routing Engine 0 REV 11 750-035700 GG0211150569 EX4500-40F Jedec Code: 0x7fb0 EEPROM Version: 0x02 P/N: 750-035700 S/N: GG0211150569 Assembly ID: 0x095a Assembly Version: 10.11 <<<======[Does NOT Includes USB Controller version 2.0 - Maj Bd Revision 10] Date: 04-07-2011 Assembly Flags: 0x00 Version: REV 11 CLEI Code: COMW610DRB ID: EX4500-40F FRU Model Number: EX4500-40F-FB-C
Routing Engine 0 REV 20 750-036562 GX0214257535 EX4500-40F Jedec Code: 0x7fb0 EEPROM Version: 0x02 P/N: 750-036562 S/N: GX0214257535 Assembly ID: 0x095a Assembly Version : 11 .20 <<<======[Includes USB Controller version 2.0 - Maj Bd Revision 11] Date: 06-28-2014 Assembly Flags: 0x00 Version: REV 20 CLEI Code: CMMHB00BRB ID: EX4500-40F FRU Model Number: EX4500-40F-VC1-FB