Only support 4G U disk?

I use nios2-linux-20100621.tar without MMU in 3C40 board.

I already update the kernel, insert 2G, 4G or less U disk, this is ok.

But insert 8G U disk, it show "Too big for this kernel. Use a kernel compiled with support for large block devices.".

I download uClinux-dist-20111111.tar.bz2 to transplante, but i failed.