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[mkgmap-dev] OT: Edge 705 firmware hacking

From Marko Mäkelä marko.makela at iki.fi on Wed Dec 7 21:18:25 GMT 2011

Two weeks ago, the USB interface of my Edge 705 broke in such a way that 
the unit no longer enters the mass storage mode. I saw something similar 
twice earlier when the FAT file system in the internal memory was 
corrupted, but back then I was able to force it by repeatedly pressing 
the Power button while the unit was connected to the computer. Now the 
FAT seems to be OK: the base map is accessible, etc. Also the connector 
hardware looks OK. I opened the 6 Torx screws and measured the 
continuity from a USB cable to the gold-plated connector fingers on the 
daughterboard, and it was OK. I suppose that the USB interface on the 
main board (SoC?) is broken. This unit is already out of warranty and 
out of production, too.

I can update firmware and maps via the SD card. So, I was thinking of 
loading a homebrew firmware update (or hacking one of the firmware 
update files that I have saved) so that I could tell the unit to write 
its *.tcx files to the SD card. Does anyone have any pointers?

This breakage was an excuse for me to buy a SonyEricsson Xperia Active.  
The hardware is nice (accelerometers, barometer, electronic compass, GPS 
accuracy comparable with the Edge, camera comparable to 10-year-old 
pocket camera, ANT+Sport, WLAN, GSM, 3G, you name it, water and dust 
proof), but it lacks a bicycle handlebar mount.

One misfeature is common with the Edge 705: unpredictable reboots or 
shutdowns. Current uptime record is 26 hours and counting. In the 6 days 
I have had it, it has entered a reboot loop several times, and twice I 
had to move the SIM card to my old dumbphone for the rest of the day, 
because I did not feel like waiting for the reboot and re-entering the 
PIN every 5 minutes.

The Android GPS software is less than nice. MyTracks could become an 
adequate data logging application if it gained support for the 
barometric altimeter, the electronic compass and the Garmin GSC-10 
wheel&cadence sensor. Currently, it only records the heart rate and the 
GPS data. I did not find any good (open source) navigation application 
with offline vector maps and offline route calculation. So, it looks 
like it will take at least a few years before Garmin navigators and 
mkgmap will become obsolete. In any case, a unit with dedicated buttons 
should be easier to use than a touchscreen device.


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