I've already done three L18 upgrades and no problems.

Things to check:

1) Back up your database using the matching PCDBA, most likely K17 or F17. I inadvertently downloading an L18 database using PCDBA K17 and the data didn't' match what I knew was programmed into the switch. BTW, when I install a PCDBA, I don't use the default directory, rather I use separate directories so that I have all the versions I need to use.

2) Using Hyperterminal, send the file as a TEXT FILE. It takes umm...not sure, but less than it takes to smoke a cig outside, nothing near an hour and half.

3) Do you see ######### as the file is being uploaded?

4) Did you burn the uploaded data into memory?

5) Move the Download jumper back to Normal.

6) Cold boot the system for at least a full minute (a ten second cold start won't clear everything - directory swapping comes to mind).

7) Use PCDBA L18 software to access the system.

I aborted an upload once when I accidentally used SEND instead of SEND TEXT FILE.

All of the quirks I've seen have been related to a lightning damaged DX-120. None of the "quirks" could be duplicated on two other systems.