63-5
Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 63 ROM Monitor Debug Commands
Note If you are using a PC to download a Cisco IOS image over the router console port at 115,200 bps, ensure
that the PC serial port is using a 16550 universal asynchronous transmitter/receiver (UART). If the PC
serial port is not using a 16550 UART, we recommend using a speed of 38,400 or less when
downloading a Cisco IOS image over the console port.

Error Reporting

Because the ROM monitor console download uses the console to perform the data transfer, error
messages are only displayed on the console when the data transfer is terminated.
If an error does occur during a data transfer, the transfer is terminated, and an error message is displayed.
If you have changed the baud rate from the default rate, the error message is followed by a message
telling you to restore the terminal to the baud rate specified in the configuration register.
Debug Commands
Most ROM monitor debugging commands are functional only when Cisco IOS software has crashed or
is halted.
The following are ROM monitor debugging commands:
frame—Displays an individual stack frame.
sysret—Displays return information from the last booted system image.
This information includes the reason for terminating the image, a stack dump of up to eight frames,
and, if an exception is involved, the address where the exception occurred.
For example:
rommon 8> sysret
System Return Info:
count: 19, reason: user break
pc:0x801111b0, error address: 0x801111b0
Stack Trace:
FP: 0x80005ea8, PC: 0x801111b0
FP: 0x80005eb4, PC: 0x80113694
FP: 0x80005f74, PC: 0x8010eb44
FP: 0x80005f9c, PC: 0x80008118
FP: 0x80005fac, PC: 0x80008064
FP: 0x80005fc4, PC: 0xfff03d70
FP: 0x80005ffc, PC: 0x00000000
FP: 0x00000000, PC: 0x00000000
meminfo—Displays size in bytes, starting address, available range of main memory, the starting
point and size of packet memory, and size of NVRAM.
For example:
rommon 9> meminfo
Main memory size: 40 MB.
Available main memory starts at 0x10000, size 40896KB
IO (packet) memory size: 5 percent of main memory.
NVRAM size: 32KB