How to remove BOOT variable (Cat 6500 IOS)

Hi, all,

we just bought two refurbished Catalyst 6500 switches which work fine except one minor problem.

One of the switches sticks at the rom monitor, when powered on or reloaded. The error message is

Autoboot: failed, BOOT string is empty

Now I know that I could point the switch to boot from a particular image like this

boot system flash

But I'd rather have these rom mon environment variables removed completely, instead of set to a specific value, so the switch will always boot the first image it finds.

I didn't find a way to clear these variables - neither from IOS (tried no boot system ...) nor from rom mon.

Shortly, what I want is this:

core2#show bootvar BOOT variable does not exist CONFIG_FILE variable does not exist BOOTLDR variable does not exist Configuration register is 0x2102

instead of this:

core1#sh bootvar BOOT variable = CONFIG_FILE variable = BOOTLDR variable = Configuration register is 0x2102

Any hints on how to achieve this? The first output is from the switch that boots just fine without an explicit image specification.

Thanks, Patrick