| Problem | Likely cause | Solution | |---------|--------------|----------| | TFTP timeout | Firewall, wrong server IP | Use SCP/USB instead | | "Insufficient flash" | Too many images | delete <filename>.swi old images | | Switch won't boot | Corrupt image | Boot from secondary, re-copy primary | | Config lost after upgrade | Version incompatibility | Restore backup config | | Stack mismatch | Mixed firmware versions | Upgrade all members |