[mkgmap-dev] OT: Edge 705 firmware hacking

Wed Jul 29 07:49:07 BST 2015

Hi,

On Tue, Jul 28, 2015 at 11:36:05AM +0200, Mayer Peter wrote:
>i saw your blog in the internet concerning edge 705. You wrote, that it 
>is possible to make a firmware update via SD-card. Is this possible?
>If yes how should i do this? Just copy the GCD file on the SD card?

I believe that you are referring to my post to this mailing list a few 
years ago.

Because I use Linux on my computers, I never used Garmin's official 
method of updating the firmware, if there is one. I got a link to a 
firmware file on Garmin's web server, similar to the one in this 
discussion that is still available on Garmin's server:

https://forums.garmin.com/showthread.php?1185-Edge-705-and-SRM

Later, when more firmware updates were made available, I edited the URL 
and successfully downloaded newer firmware files, and then (as the above 
link says) copied them as gupdate.gcd to the root of the SD card.

These files are long gone from the Garmin server, I think. Anyway, I 
saved the following files (the numbers are file sizes in bytes):

 3323420 Edge605_705_260.gcd
 3324700 Edge605_705_270.gcd
 3325980 Edge605_705_280.gcd
 3466020 Edge605_705_290.gcd
 3468836 Edge605_705_310.gcd
 3472932 Edge605_705_320.gcd
 3479123 Edge605_705_330.gcd

The files look uncompressed to me. In the end, I did not bother hacking 
the firmware, because I did not want to risk bricking the device.

>My edge shows a similar phenomenon, it can’t store any activity data on 
>the USB mass storage but you can access its mass storage via PC / Mac.

AFAIU, the Edge 705 never writes activity data to the MicroSD card. It 
only stores it in the internal memory, first in an internal format and 
then converted to the XML-based TCX format. You can store maps 
(gmapsupp.img), GPX routes and firmware updates on the MicroSD card by 
using a computer. When the Edge 705 is connected to a computer, it 
exports two usb-storage devices: the FAT partition of its internal 
flash, and the MicroSD card.

Did you try a factory reset (press the buttons Power+Mode)? Or did you 
try pressing Power+Up? The Garmin firmware is buggy. I got some random 
trouble with all the above firmware versions. Sometimes it would crash 
when converting the stored data from its internal format to the 
XML-based TCX format, and I had to write a script to stitch the pieces 
together. Sometimes it would write some garbage to a TCX file.  
Sometimes it would crash while recording. Once it corrupted its internal 
FAT file system, and I had to carefully repair it via the usb-storage 
interface.  A few months after that, the data lines of its USB port 
failed, which made the device useless for saving any GPS traces.

>I would like to update the firmware again but did not succeed.
>Did you solve your problem?

I switched to an Android phone. My Edge 705 sat idle for a few years, 
until I sold it to a friend a few weeks ago.

Best regards,

	Marko