CCNA · DEVICE MANAGEMENT

Troubleshoot a failed IOS upgrade

A colleague tried to upgrade R1 (Cisco 2911) from 15.7(3)M8 to 15.9(3)M9 and gave up: the copy failed, and the boot system line they saved has a typo. R1 still runs 15.7(3)M8. Finish the upgrade. The published MD5 of c2900-universalk9-mz.SPA.159-3.M9.bin is d4d4724eeab343dfa86596645a7135c5; the TFTP server is 10.0.0.100.

CCNA ER track · Cisco IOS · 5 objectives

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Objectives

The simulator ticks each one as soon as the network meets it.

Find why the upgrade failed: dir flash:, show boot and show version.
Free flash: delete the old 15.4(3)M image nobody uses.
Copy 15.9(3)M9 to flash: and make sure its MD5 matches the published one. A corrupt copy must be deleted and copied again.
Fix the boot variable so R1 boots flash:c2900-universalk9-mz.SPA.159-3.M9.bin, and save.
Reload: R1 runs 15.9(3)M9.

Start this lab

Before you start

dir flash: shows the free space; the new image needs about 114 MB. verify /md5 without a hash prints the file’s signature, so you can compare it by eye; with the published hash it says Verified or Error. TFTP has no checksum of its own, so a transfer can arrive corrupt. A boot system line that names a missing file is skipped at boot.

Concept

Upgrading classic IOS: copy, verify, boot system, reload

Classic IOS (and IOS XE in bundle mode) boots one image file. An upgrade copies the new image into flash, checks it is intact, tells the router to boot it, saves that setting and reloads. Every step can fail on its own: no room in flash, a corrupt transfer, a typo in the boot variable, or a boot variable that was never saved.