Hi, I did the same and I though I had the most expensive paperweight until I read this post and it worked.Kudos to svintuss for his solution.
I have a Garmin Colorado 300 with 3.50 firmware. 2 days ago it froze twice so i decided to format it's internal memory. For that I used the "disk utility" from my mac. After that I did a master reset and I noticed that when asked for the language I got a "Ó" as only option, I could edit , change profiles o select maps. When I pluged it to my mac it wouldn't got into usb mode it stuck in "Loading profile...", I had to click and hold the top part of the roller button to start the usb mode. In usb mode I could see the gps didn't recreate any file (I was expecting at least the garmin folder and the garmindevice.xml file), webupdater did see the gps but it failed when trying to restore the firmware. I connected the gps to an old pc I have and noticed I could install maps and get the unit number and I even install an older version of the firmware but when restarting the colorado nothing happened.
Then I saw this post in the ColoradoWiki http://garminoregon.wikispaces.com/message...w/home/12867249 and decided to try it.
On the mac, or it could be any computer with unix's dd command I executed "dd if=/dev/zero of=/dev/disk1"(disk1 being the colorado) to zero all the colorado's memory, this took a couple of hours. When finished, I connected to the pc computer and I did a Fat (fat16) format of the gps (don't use the mac for this). I started the gps after doing a master reset and the I saw I could choose English as language. i plugged it back to the mac and entered usb mode without problems,I saw the garmin folder with one recreational profile, the gpx folder and the Wherigo folder. Problem fixed.
The reason mac's disk utility screwed the colorado is becasue, in my case it renamed the gps from /dev/disk1 to /dev/disk1s1 after the format. Zeroing the gps with dd and formating it to fat16 on windows restored the gps disk unit to /dev/disk1. If you are curious this is what it recreates after the formatting and booting up:
MacPowerBook$ ls -R /Volumes/COLORADO
Garmin Wherigo
/Volumes/COLORADO/Garmin:
GPX Profiles
GarminDevice.xml startup.txt
/Volumes/COLORADO/Garmin/GPX:
Current
/Volumes/COLORADO/Garmin/GPX/Current:
Current.gpx
/Volumes/COLORADO/Garmin/Profiles:
Recreational.gpf
/Volumes/COLORADO/Wherigo:
Logs
/Volumes/COLORADO/Wherigo/Logs:
WherigoLog.log
Now all I have to do is restore the backup I made when I bought the colorado.
I formatted the colorado on the mac because I did the same thing with a Garmin Nuvi 265W and nothing wrong happened so I thought it would be good the colorado too. My mistake.
