The Kernel on the GTA01 is based on a vanilla 2.6.17.7 Linux kernel from kernel.org.
Some additional patches are required for
The latest patchset against the abovementioned vanilla kernel can be found at [1]. This is a so-called "quilt patchset". In order to apply it, you have to untar it into a "patches" directory below the "linux-2.6.x" directory, and then call "quilt push -a", which pushes all patches onto the kernel.
The latest kernel configuration can be found at [2]. Just copy it to the linux-2.6.x/.config file.
The kernel build is executed as normal. We actually only need the "vmlinux" target, not the "zImage".
A bootable kernel image called uImage is available from [3]
u-boot needs all images (such as kernel, initrd, ...) in the form of an uImage. This is basically just a special header adding CRC protection, version information, etc. Pleaes see u-boot for details.