In message 91C99CB54D033E469E6D6702BAE5744701CEF3F7@dbde01.ent.ti.com you wrote:
I tried to dig into this issue, and found that, U-Boot for NAND Flash is designed the same way. The function "nand_init" gets invoked after "env_init" and "serial_init", and sue to this U-Boot always uses the default baudrate.
Thjis is a dilemma - U-Boot tries to support porting and debugging by enabling the serial console very, very early, typically long before relocation to RAM. In this state, we have only a verly limited environment - small stack, no writable data segment, no BSS, etc. This is not sufficient for the (pretty complicated) NAND flash driver. So U-Boot cannot read the baudrate setting from the environment in NAND...
Best regards,
Wolfgang Denk