In message 444F91D0.9080904@orkun.us you wrote:
Yet, the default environment normally does not contain such important stuff like ethaddr which is assigned per board.
If you consider params like MAC address and serial number critical, than make sure they hetinitialized automatically; see for example board/tqm8xx/load_sernum_ethaddr.c; here a special information block will be written to a reserved area in flash (done as part of the production, when MAC address and serial number get assigned to the board. If they are not set in the environment, U-Boot will automatically pick the values from there. Thus you can combine a common default environment with board specific parameters like serial# or ethaddr.
Just look around a bit in the code. Many problems have been solved before. Don't reinvent the wheel. Steel the code - it's free software.
Best regards,
Wolfgang Denk