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Purpose of C6500 IOS boot images

I'm a bit puzzled about what exactly the "boot-mz" files are needed for on C6500 SUP32 and SUP720 platforms.  Are they really mandatory, or do they serve just as backups in case the main IOS image (or the flash media it resides on) gets damaged?  Should I put such a boot image on the SP's or the RP's bootflash?  I see that there are no boot image releases beyond 12.2.33-SXI12 - does this mean there's no use for a boot image with IOS 12.2.33-SXJ and later?


Thank you.


Hi, ivaideanu...The "boot-mz"

Hi, ivaideanu...

The "boot-mz" files is bootflash image not a full-featured so-called Universal Boot Loader Image.
According, for example, to (
"The Universal Boot Loader (UBL) image is a minimal network-aware image that can download and install a Cisco IOS image from a running active supervisor engine in the same chassis. When newly installed as a standby supervisor engine in a redundant configuration, a supervisor engine running the UBL image automatically attempts to copy the image of the running active supervisor engine in the same chassis"
Generally, you do not need it...

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