Suggestion to test TomTom can't write beyond 4Gb SDHC card

[saikee]

My unit is a TT920T

I have used a 4Gb and 8Gb SDHC cards before and everything seems to run alright but people in the forum keep saying TT can't write beyond 4Gb.

The common way to test it is to ask TT to write/record the favourites.

I now got hold of a Transcend Class 6 SDHC with 16Gb capacity.

To test it I filled up the 16Gb SDHC card with 6Gb of MP3 first, then another 6Gb of photos to make sure the first 11 to 12 Gb is filled.

I then loaded the North American map, about 1.4 Gb large, onto the SDHC card from a backup in a PC. I then inserted the card into TT and chose a dozen places recorded as favourites and TT accepted them.

I am running out of idea to find a way to prove TT can't write beyond the 4Gb barrier. So far it doesn't seem to have such a limitation. My MP3 plays well and I can see all my photos which are between 3 to 4 Mb each.

Any suggestion?

[Kar98]

As far as I've tested:

The TomTom device is able to run off, and read and write to SDHC cards without any problems.
You can connect your TomTom to your computer, or put the card into a compatible reader, and Windows Explorer/OSX Finder can read and read the card just fine (tested with WinXP and OSX 10.5, and a 8 GB SDHC card).
Even TTHOME recognizes and reads/writes to the card when it is in a reader or any other SDHC-compatible device other than my TT.
The only time when I'm experiencing problems is when I tell TomTom Home to access the SDHC card while it's in the TT.

[saikee]

This is still my case.

I am trying to bottom out the problem with large capacity SDHC cards.

If the SDHC card is 4Gb, the same size as the one inside TomTom then the PC software "TomTom Home" can see it and use it. Also the PC detects TomTom as a twin-disk system and able to read both disks without going through "TomTom Home". That to me is the base condition.

There are two problems reported in the forum.

(1) Problem 1

If the SDHC card is larger than 4Gb then the PC sees the TomTom unit still a twin-disk device but the larger SDHC card is detected as unformatted so it cannot be read. If the same card is removed from TomTom and put into a normal USB card reader it works normally.

I believe this is to do with a bug in the software "TomTom home", as the large capacity card functions normally as far as TomTom is concerned in any day to day operation as a Sat Nav system.

(2) Problem 2

Many forum members reported if a SDHC card larger than 4Gb is used in a TomTom when it operates as a Sat Nav unit (not connected to a PC) then TomTom cannot write beyond the 4Gb barrier. They suggested to test TomTom's ability to write on it is to record the favourites, thereby making TomTom to write.

There never has been any problem for TomTom to read a large SDHC card but there seems to be a consistent complaint SDHC cards larger than 4Gb cannot be written on by TomTom.

My thread here is to report that I seem to be unable to find such evidence. My TomTom was able to record favourites when I use a 8Gb SDHC card. Now I got a 16Gb SDHC card and still no problem in recording the favourite when I made sure the NA map is installed well beyond the first 10Gb.

I am running out of idea to check if the Problem 2 exists.

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