I purchased a used Aastra 57i SIP phone from a seller on Amazon and, unfortunately, it was one of the very few whose admin password was NOT the default ’22222′.  The seller had purchased it in a bulk liquidation and didn’t have any of the details, so I was left to scour the web to figure out how to get the 57i back to a factory-fresh state.

Google came up with a rare zilch (most of the posts I found said to hit ’4′ & ’6′ or ‘*’ & ‘#’ during startup, but that didn’t work).  A call to a very helpful rep at Aastra solved the problem:

To hard reset an Aastra 57i or 6757i when you do not have access to the admin password, you’ll have to put the phone into its emergency ‘web recovery’ mode and reload the firmware from a TFTP, FTP or HTTP server.  Do the following:

1. Disconnect the phone from any outside network and run an Ethernet cable from the ‘PC’ port on the phone directly to your machine.
2. Boot up the phone in Web Recovery mode by holding down the ’1′ and ‘#’ keys during phone boot (hold the keys down and then plug in the power on the phone).
3. Check the IP address on the screen of the phone, and set your computer’s IP address to something in the same subnet (for example, my Aastra gave itself an IP address of 169.254.168.234 so I setup my machine to have 169.254.168.233).
4. Get a TFTP or FTP server running locally on your machine.  If you’ve got a Mac, Tfttserver is a good one.
5. Put the latest 57i.st firmware file on your local TFTP/FTP server.
6. Point your browser at the IP address displayed on the phone and you should be greeted with the Web Recovery screen.
7. Enter the location of the 57i.st file and your TFTP/FTP server — *IMPORTANT – AND THIS DROVE ME NUTS:  Every time I tried to start the download in Chrome or Safari by clicking on the button at the bottom of the form, I got an “Invalid Parameters” error message.  I had to use Firefox and be sure to hit enter after typing the details instead of clicking on the submit button — that got the file to download.
8. Voila — fresh new firmware in a full factory default state.

Hope this is helpful!