Check existing version
SW1# show version
Check existing boot location
SW1# show boot
Backup existing version
SW1# copy flash:c3750-ipbasek9-mz.122-25.SEE3.bin tftp:
Download new IOS and verify MD5
SW1# copy tftp flash SW1# dir flash: SW1# verify /md5 flash:c3750-ipbasek9-mz.122-25.SEE3.bin
Get-FileHash on Windows
dir Get-FileHash <filepath> -Algorithm MD5 Get-FileHash .\c3750-ipbasek9-mz.122-55.SE12.bin -Algorithm MD5
Ask switch to boot from new file
SW1(config)# boot system flash:NewVersion.Bin SW1(config)# do show boot SW1(config)# do wr mem SW1(config)# do reload
After successful reload, delete old IOS
SW1(config)# show flash SW1(config)# delete flash:OldFile.Bin