You may use U-boot command “clocks” to get information about DDR frequency.
To change default after reset configuration of i.MX6, DCD table may be used.
Please look at the following :
“Need to modify the "flash_headers.h" file from u-boot for DDR3 modification”
https://community.freescale.com/message/548227#548227
Also, please refer to i.MX6 Reference Manual, boot chapter for more details.
Have a great day,
Yuri
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------