the question of the starting of uclinux by u-boot

1. maybe you should check the hardware of your board in more details.

you should run from onchip memory and do a lot of sdram tests, and check the timing/functionality of your board.

2. if you want to run uclinux, it is better to use S-core, with a small icache, eg 512Bytes.

the E-core is too slow. If you use CycloneII, use hw mul.

3. you can use initramfs with the kernel. so that you need only one kernel image to boot, instead of three. After you are comfortable with uClinux, you can try compressed loader then.