I still don't know why the firmware upgrade process failed BUT after performing the above sequence I found that the firmware upgrade had actually worked (strange). Here are some of our favorite tips to get the most out of your Garmin nüvi 255W GPS with EasyGPS and ExpertGPS, our full-featured mapping software. I hope this assists other if they encounter this problem. Once the pre boot mode message disappears release the power button and your device will perform some activities to recover from the above problem.Īpparently this sequence will only work with the above error. This seems to take a long time (60 seconds at least).ģ. KEEP HOLDING the power button down and the display will flicker, do this until the pre boot mode message disappears. HOLD down the power button and you will see "Pre Boot Mode" appear on the lower part of the display. I contacted the local Garmin support rep and I was given the following sequence to recover from this condition:Ģ. When the unit came back up again the following error came up on the screen: I could not work out a way to recover from this as the upgrade failed (not fully complete) and the only option was to reset the unit via the power button. bin files copied to the unit but the third file (I can't recall the extension) failed to copy with a file in use error. I ran the firmware update as per the instructions from the Garmin website and two. I did this as I read some other comments that the Garmin webupdater application has (in some cases) caused corruption. I recently downloaded the Nuvi 660 firmware upgrade from the Garmin site to upgrade to v2.70.