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Can't access USB ports following upgrade (1941 router)

Group IT
Level 1
Level 1


I have been using 'dir usbflash0:' etc on a Cisco 1941 router with IOS v15.1 fine.

Today I have upgraded the IOS to c1900-universalk9-mz.SPA.155-1.T.bin and also tried c1900-universalk9-mz.SPA.155-3.M3.bin.

With these new IOS's I am unable to access the USB ports. If I downgrade back to 15.1, they work fine again.

Under 15.5, 'dir ?' doesn't seem to show the filesystems for USB being available:


rtr-h001859#dir ?
/all List all files
/recursive List files recursively
all-filesystems List files on all filesystems
archive: Directory or file name
cns: Directory or file name
flash0: Directory or file name
flash1: Directory or file name
flash: Directory or file name
null: Directory or file name
nvram: Directory or file name
system: Directory or file name
tar: Directory or file name
tmpsys: Directory or file name
xmodem: Directory or file name
ymodem: Directory or file name
| Output modifiers


However I can issue 'show usb' and it shows them active:


rtr-h001859#show usb port
Port Number: 0
Status: Disabled
Connection State: Disconnected
Speed: Unknown
Power State: ON

Port Number: 1
Status: Enabled
Connection State: Connected
Speed: High
Power State: ON


I have tried running "no hw-module usb disable", saving and reloading, but still nothing.

Do later IOS's really disable use of the USB ports?!

I would really appreciate some insight or advice on how to access the USB ports under 15.5+.

Thank you!

Best Regards,


2 Replies 2

Leo Laohoo
Hall of Fame
Hall of Fame

Do later IOS's really disable use of the USB ports?!

This issue is caused by a bug in the IOS code.  I've seen this before.  Nothing you can do except upgrade (or downgrade).

Hi Leo,

Thank you for your reply.

I don't suppose you know of a paper which references all the buggy (or even non-buggy) IOS's do you?

I have now tried the following IOS's and they all have the same issue!







I'm actually wondering if the problem is due to a "default" config setting which one of the later IOS's introduced.

Also, like an idiot, between shuffling all these IOS files about, I have managed to delete the original IOS which was on the device, so now I am unsure exactly which one did work!

Thank you.

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