@MikeD82
I moved the above post here from Trouble with Garmin 255w thread and merged them. Don't open a new thread for the same topic. Post again only in here for your problem please.

255W US have 2 possible HWIDs, usual is 0872 but there's also 1091 [MTK chip]. You may have made the cure using the wrong firmware, that message indicates the fw isn't suitable for the device. Check the unit's HWID by looking at a backup if you have one. Look in the Garmin folder for GarminDevice.xml and open it with a text reader or internet browser. Look for this near the start: <Model><PartNumber>006-BXXXX-00</PartNumber><SoftwareVersion>xx0</SoftwareVersion><Description>nüvi 255W</Description></Model>.

XXXX is your HWID. xx0 is the current fw on the unit. Latest is V7.80: [Only registered and activated users can see links. ].

If you don't have a backup, give yourself a good talking too and promise yourself to not forget to do that again. However, you can get your HWID and FW version using [Only registered and activated users can see links. ] in [Only registered and activated users can see links. ]. Lots more info in the [Only registered and activated users can see links. ] too.

Seeing your unit was bricked by GarminExpress being interrupted, it may not be badly bricked and simply stuck on the splash screen loading maps because the gmapprom.img is corrupt. It may be worth trying QuickCure first, because it's universal and doesn't need the original firmware. You can find the info on that towards the bottom of kunix's initial post of [Only registered and activated users can see links. ]. If you can get it into Mass Storage Mode with cure/quickcure, just delete gmapprom.img and gupdate.gcd [if present] from the Garmin folder, don't do a re-format and then flash the original firmware in pre-boot and it'll probably be okay. Then update it again to replace the detail map with GE or better still use [Only registered and activated users can see links. ], it's safer imo. [Only registered and activated users can see links. ] is safer for software too.