HI,
I created an image of the firmware version G5S50033B34 with the MAC address 7AB4F50016B3 -
Downlaod Link
IT's a rar - unrar it and you have the 8MB file. Check that it is exactly 8.388.608 Bytes in size.
This file can be flashed using the option "X:Upgrade Boot"
Be very careful as this overwrites the bootloader, too. It will take about 15 minutes.
You have to change the MAC address to yours (you should find a sticker somewhere on the board)
You can edit it with a hex editor (e.g. frhed - offset 8126651/0x7c00bb) directly inside the image before flashing or later by the bootloader. Search for the MAC (ASCII text) and change it.
HWguru