blog.mbirth.de

A while ago I was fed up with Android Wear smartwatches and bought a Garmin Fenix 5 Plus. After using it for a while I started to explore the possibilities beyond the manufacturer specifications. This lead to a firmware patcher based upon work from Alex Whiter (who sadly passed in 2019). That patcher modified the firmware update file and disabled the license check for Garmin Maps. After installing a patched firmware, you were able to use any downloaded Garmin map on the watch without having to buy a license. Alex himself also offered a patcher to enable the use of custom made JNX "BirdsEye" files. (These JNX files can be easily created with SAS.Planet / SAS.Планета, a Windows tool to download map tiles and export them to different formats.)

These patchers sparked my interest in the firmware format as I've noticed they not only patched the few Bytes in the code but also modified other areas in the file.

There are some hidden options which you have to enable via modifying some file. (see here and here.)

The Sansa's have different features for different countries/regions. E.g. the Japanese radio frequencies ranging from 76 to 90 MHz are partly used for Police radio and thus it is not allowed to tune to these forbidden frequencies.