I figured that part out a couple of weeks ago, what I need to find out is how, step by step, to load the new image from the usb drive onto the file system and then get the router to boot the new image, thats what I'm hazy about. I've put a lot of routers in and configured them but never a upgrade or IOS change. I usually install, configure and thats it for 3 or 4 years.
I have not actually used the USB capability on a router yet so this response is based on what I have read but not on any actual experience.
First a caveat: the documentation states pretty clearly that the USB needs to be a "cisco" USB rather than some generic USB. So do you have a "cisco" USB?
I would assume that the best way to check it would be to insert the USB and see if the router recognizes it. If you can do a dir (or a show) on usbflash0 or on usbflash1 then you should be good to go.
If the router recognizes the USB you should be able to boot directly from the USB. I would expect there to be an option in the boot system command to specify the USB as the filesystem for the image (boot system usbflash0: or boot system usbflash1:).
Or perhaps you might want to try to copy the image from the USB into the usual flash so that the router is not dependent on the external boot source during normal operation. I would expect that copy ? would show usbflash0 or usbflash1 as a possible source for the copy operation.
Actually experimented with the USB features on a 2811 a month or so ago.
It seemed generic USB sticks work, but there was an issue with size (64 MB or under?) and/or format (FAT?). Sorry, don't recall the specifics, but we tried a few different brand X, all seemed to work fine if they had what was expected.
Also, I recall there might be a requirement that the bootrom needs to be at 12.4(13r)T5, if you want to actually boot off it.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...