We're developing custom board based on IMX53QSB. Kernel 2.5.35 from LTIB works fine. u-boot from LTIB works fine.
Even u-boot from git works fine (and with 1Ghz clock).
Linux kernel 3.8.2 compiles with imx_v6_v7_defconfig, but hangs up on device. And I can't understand why: load address? Entry point? DRAM setting (but it's U-boot's work)?
Can you public you .config or at least .diff from imx_v6_v7_defconfig?