Yes, the entire 2800 series (2811, 2821, 2851, 2801) uses this unified image.
On the router, verify connectivity:
Once you have the file on a TFTP server (e.g., 192.168.1.200 ), you can use the following command to upgrade your router as suggested by experts at NetworkLessons.com : C2800nm-adventerprisek9-mz.151-4.m12a.bin Download
Use Cisco's official channels only. If you cannot legally access it, migrate to a modern platform (Cisco 4000 series with IOS-XE) or use open-source routing (VyOS, pfSense) for lab environments. Yes, the entire 2800 series (2811, 2821, 2851,
# boot system flash c2800nm-adventerprisek9-mz.151-4.M12a.bin Router(config) Router# copy running-config startup-config Router# reload Use code with caution. Copied to clipboard After reloading, you can verify the version by running show version | include image NetworkLessons.com to your router using a TFTP server Solved: Cisco 2851 Router - Cisco Community # boot system flash c2800nm-adventerprisek9-mz