I tried upgrading code on a switch to 12.2(18) SXF7.
I had 12.2(18) SXF7 loaded onto a PCMCIA flash card that was inserted slot 0.
So, I changed the boot system commnads to the following:
boot system flash disk0:s222-adventerprisek9_wan-mz.122-18.SXF7
boot system flash sup-bootflash:c6sup22-jk2sv-mz.121-13.E13
I wanted the 12.2(18) to load first and if it failed to use the old code as a backup.
The switch wouldnt load the new IOS until I added the ".bin" file extension to the boot system command for the 12.2(18) SXF7.
Why did I not have to do that for the old IOS that was in sup-bootflash and that I left as a backup?
It was a 6500 switch with a SUP 2 module.