I have a GPS Becker 7934 with Wince4.2 and 1GB memory card.
I would like to upgrade to 4 GB SDHC but this unit can't read. Any solutions?

Probably not, Your device doesn't look like it supports SDHC

This unit can't read FAT32. Maybe flashing the rom?

SD and SDHC are two different things, If you can find a ROM with a SDHC driver in it, then yes it will work.

I tried to install the drivers .cab on WinCE4.2 but don't recognize the new card.
The ROM of my unit is EC102. I tried to find a ROM with SDHC driver included but I did have not lucky.
As I haven't sure about others of ROM's versions, I don't found changelog's files about EC104, EC105 and EC107. Do you know where can I find these informations?

They might not have been published, And as this is a wince 4.2 device, any changes to the windows directory or the registry won't be saved when you turn the device off, none of the rom's for my wince 4.2 device support SDHC

FYI, there is a 4GB SD [not SDHC] card available somewhere - sorry, but I don't have a link. You can use a 2GB SD card but it would limit your navs and contents.

EDIT: Personally, I wouldn't suggest that you flash. The slightest hiccup in the process will brick your device. I hope that you made a complete backup of your device's files/folders before you flashed in case you need to reinstall the old stuff.

CE4.20 is originally limited to only sd cards. A flash rom MIGHT upgrade the WindowsCE to sdhc, but it won't upgrade the hardware. Meaning that when your card reader is hardware limited to sd, your device will never ever read sdhc cards.

I think that 4GB SD (not SDHC) is best solution for my unit. I'm trying to find a memory card that's support FAT16, but it's very hard to find anywhere. Thanks for all.