CatOS which is already EoL, there are many companies out there which are still using CatOS. Problem arises when SUP 720 or SUP 32 running CatOS fails and new RMA SUP comeswith IOS on it. if you have the luxary of the spare switch to do the IOS to CatOS conversion, it is cool. What if there is no spare switch to do the conversion. The only option left is the Production Switch.
Here is the step by step, how to do it on the production switch:
1) copy the CatOS on the external flash disk of the RMA SUP.
2) Install the RMA SUP with Console cable connected into the chassis which already have Primary SUP running on CatOS.
3) As soon as it starts to boot, use CTRL+Break to getinto ROMMON. Dont let the RMA SUP to boot with IOS(Switch will crash in next 5 mins).
4) form ROMMON use the boot command to boot it from CatOS stored in the external flash.
5) Here u go....RMA SUP is up with CatOS and will go into standy mode.
Plz refer the attached document for more details.
Plz feel free to let me know if you have any questions about it.
Happy Converting in prodcution....