This has nothing to do with vintage computing. I wear a Garmin GPW watch when I'm running. The model is Forerunner 15 with version 2.40 of their firmware. The latest firmware is version 2.70. Officially, they require Windows software Garmin Connect to download the firmware and synchronize it to your device. Garmin Connect in turn requires a late-model version of .NET Framework. I couldn't get .NET Framework to install in WINE, so I started Googling for manual upgrade methods. I found a few relevant posts: https://forums.garmin.com/forum/into-sports/running/forerunner-620-aa/70154-... https://forums.garmin.com/forum/into-sports/cycling/edge-520-aa/125491- Both posts indicate a method of downloading the firmware file manually (done), changing it from (filename).rgn to gupdate.gcd, attaching the watch via its USB charging gadget to your computer, putting the file in the right directory, dismounting the device from Linux, and rebooting the device. Easy enough ... except nothing happens when I reboot the watch and its settings menu still shows version 2.40. There are posts about editing out part of the file using a hex editor, for example, post #6 in the first link that I put above. I downloaded a hex editor and can see the data but I have no clue how to use it. The file is on my personal site: http://www.snarc.net/forerunner15_270.rgn Lil' help?