(shamelessly copied from Flexible's post 2012-Apr-11):
To reset the FortiGate unit password
1. Connect the terminal to the FortiGate unit using the null modem cable.
- any Cisco type serial DB9-to-RJ45 cable will do
- should be at 9600/8/N/1, if not, try other speeds up to 115k until you get a prompt
NOW: power OFF the FGT! next step will only work for a short period of time (seconds) after a power up!
2. Log on at the console* with
You must enter the alphabetic characters of the serial number ...exactly as given, that is, in upper case
3. Enter the following commands:
config system admin
set password <mypassword>
4. Log off, and on again as "admin"/<mypassword>. The maintainer cannot do much except for resetting the admin password.
5. in the CLI: "exec factoryreset" to clean the config up
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