XDA forums people have managed to make ‘Google Maps Navigation’ workable outside US, and ‘Navigation’ can now work on your G1 along with the navigation features in Canada, Europe, Asia or anywhere in the World.
Details of how to get navigation working can be found over on this thread.
To get the application working with Navigation on your G1 then follow the instructions below, but I highly recommend you read over all the details on XDA Forums to make sure you get the install right.
If you have root, uninstall the current Maps app.
adb shell rm /system/sd/app/*Maps*
adb shell rm /system/sd/app/*maps*
adb shell rm /system/sd/dalvik-cache/*Maps*
adb shell rm /system/sd/dalvik-cache/*maps*
adb shell rm /data/app/*Maps*
adb shell rm /data/app/*maps*
adb shell rm /data/dalvik-cache/*Maps*
adb shell rm /data/dalvik-cache/*maps*
adb shell rm /system/app/*Maps*
adb shell rm /system/app/*maps*
adb uninstall com.google.android.apps.maps
Next, install the SpeechSynthesis Data. You can do this either by going into the market and searching “SpeechSynthesis Data Installer”, or on some ROM’s, like CM 4.2.5, Menu -> Settings -> Speech synthesis -> Install voice data
If you have root, download http://drop.io/rxbqaw4/asset/maps-root-aligned-apk
If you do not have root, download http://drop.io/rxbqaw4/asset/maps-no-root-aligned-apk
Install the new file:
adb install -r maps-root-aligned-apk
adb install -r maps-no-root-aligned-apk