I've seen a lot of posts regarding the way in which a 6500 finds its boot image. None of them have answered my question, so here goes:
I have a 6504E running Native IOS that I use in a lab environment. I'm running the image s72033-ipservices_wan-mz.122-33.SXI2.bin, and it's too big to fit on the 64 MB of flash in my 720 supervisor (image is 96+ MB). So I can't copy the disk0 image to sup-bootflash. When I have a config loaded, I specify the 'boot system disk0:s72033-ipservices_wan-mz.122-33.SXI2.bin' command and all is well. However, since this is in a lab environment, I often clear the startup config and reload it. Every time I do that, the system loses that boot system command and I have to type the boot command followed by the image location from rommon. This is getting tiresome, especially when I think there's probably a way to avoid this. None of the documents I have read tell me how this can be solved. So in short, image is too large to fit into sup-bootflash and the switch doesn't have a boot system command to read. I also tried set commands (i.e. BOOT=disk0:s72033-ipservices_wan-mz.122-33.SXI2.bin) and then just typed 'boot' and it couldn't find an image.
Maybe not entirely what you are looking for, but it could also solve your problem.
When you have a blank config, configure your boot statements (boot system flash disk0:....) and save it to a file:
copy running-config disk0:blank-cfg
Then, when you want to have a blank config again, instead of wr erase - reload, just revert back to the blank config you initially created.
configure replace disk0:blank-cfg
This will replace your current running config with the blank config that contains the boot statements. If required, you can reload your switch and it will have the correct boot string.
Didn't test it though, but normally this should work.
Maybe you can test it and let us know if it works?
A very clever idea indeed. I'll give that a go in my lab in the next week or so and let you know how it went. Sounds like a winner to me ...
You can also do the following 3 commands from rommon:
then it will automatically boot the image from disk0.