Unknown mode CISCO 2511 Access Server upon Boot

[dradpeters]

I recently took possession of a 2511 Access Server, and 

Connected a console cable to my MacBook Pro.

Turned on the machine. 

Opened a terminal and had a connection with the server.

The prompt I see is: >

What mode is this and why don't I see ROMMON or Router mode?

Typing H after the prompt I see the following:

$            Toggle cache state

B [filename] [TFTP Server IP address | TFTP Server Name]

             Load and execute system image from ROM or from TFTP server

C [address]  Continue execution [optional address]

D /S M L V   Deposit value V of size S into location L with modifier M

E /S M L     Examine location L with size S with modifier M

G [address]  Begin execution

H            Help for commands

I            Initialize

K            Stack trace

L [filename] [TFTP Server IP address | TFTP Server Name]

             Load system image from ROM or from TFTP server, but do not

             begin execution

O            Show configuration register option settings

P            Set the break point

S            Single step next instruction

T function   Test device (? for help)

Deposit and Examine sizes may be B (byte), L (long) or S (short).

Modifiers may be R (register) or S (byte swap).

Register names are: D0-D7, A0-A6, SS, US, SR, and PC

[dradpeters · Accepted solution]

As a beginner, with limited information, it was difficult to solve the issue. All I had was a ">" prompt with no idea what that was. Looking for modes in searches brought back little on this. Eventually, I came across this somewhere:

• https://www.cisco.com/c/en/us/support/docs/routers/2500-series-routers/15078-recovery-c2500.html

Verify the Configuration Register Value

The first thing that needs to be investigated is why the router is booting up in ROMmon mode indicated by either of the 2 prompts:

• rommon # > 
• > prompt

Determine whether the cause is due to the change of the configuration register value, or a corrupted Cisco IOS software image.

If the router has a valid Cisco IOS software image, then simply changing the configuration value register to 0x2102 will recover the router. The procedure for this is explained in the link, and briefly below:

1. If the prompt is ">", type the following at the ROMmon prompt:

>o/r 0x2102

>i

... and then give it time to boot.

If it comes into the mode "Router>" then changing the configuration register booted the server. If not then the IOS is probably corrupt. There are additional procedures at the link if this is the case.

The procedure for "roman #>" prompt can be found at the link above.