[U-Boot] Questions about U-boot of customized MPC8315E board

[du zhenhuan]

Hello, 
I'm a newbie using U-boot and met  several problems 
with a customized board based on MPC8315E-RDB board.
On the new board, I have changed the Ethernet PHY to TI's DP83848 
 and NAND FLASH to  64Mbit (from old 32Mbit).


During U-boot form NOR FLASH , I met two problems :


1, if NAND flash support is enabled, 
U-boot just print out  "NAND : "  without size info and then print out text like "machine check ...,",
 then print out "resetting board ..."
So the board keep resetting again and again.
Does this  have anything to do with NAND FLASH size change or  NAND PART types?


2.if NAND flash support is disabled,
 U-boot just go to Ethernet PHY  initialization part and print out that DP83848 is not supported ,
Where can I put new driver to support it?


3.How can I watch more ouput infomation during U-boot boot process to debug these problems ?


Thanks.