A new revision of the NSE-100 (Hardware Revision 5.0) is being introduced. This revision requires Cisco IOS® Software Release 12.1(12c)EX1 or later.
The new revision (5.0) of the NSE-100 is being released to address end-of-lifed components; to replace some components with improved, newer technology versions; and to add an enhancement in hardware Field Programmable Gate Arrays (FPGAs) so that software can check during bootup if they are actually operational. Some of the replacements are not backward compatible. For example, the SDRAM memory chips used for data storage on the PXF processor are being replaced because the vendor is terminating production of those chips. The replacement chips available require configuration of different timing parameters and are not compatible with Cisco IOS Software releases earlier than 12.1(12c)EX1. The FPGA enhancement introduces new FPGA code versions on the NSE-100.
The first time a Cisco IOS software release earlier than 12.1(12c)EX1 is loaded on this NSE-100 version, it will prompt for FPGA downgrades on the NSE-100. There are two such FPGA's - the Motherboard (MB) FPGA and the Daughterboard (DB) FPGA.
If the DB FPGA is downgraded, then any subsequent reload will cause the ROM Monitor code in the golden boot ROM to upgrade this FPGA with a later version. If the same pre-12.1(12c)EX1 Cisco IOS software is loaded, the Cisco IOS software image will try to downgrade it. The upgrades and downgrades will take tens of minutes and keep the system out of service for an extended time. System operation during the upgrades and downgrades is not recommended in order to minimize or eliminate any chances of interruption to the upgrade or downgrade process.
If the MB FPGA is downgraded, then any subsequent reload with a pre-12.1(12c)EX1 Cisco IOS software image will fail due to a MISTRAL_IO_BUS_INT_MASK_LO related fatal error interrupt. See Error 1 below for more details on the error.
If the MB FPGA is not downgraded by responding with n to the Downgrade slot NSE MB FPGA ? [y/n] prompt, the pre-12.1(12c)EX1 Cisco IOS will fail to load due to PXF exceptions. See Error 2 below for more details.