Should I calibrate my board for 512 mb or 1Gb

[sujay1]

I have a custom imx6solo board which has 2 ddr chips of 512MB each. 

I calibrated the ddr values for 512 mb and the board boots fine. However when I calibrate for 1Gb the board goes into kernel panic while trying to init bootm (android logo comes up at this stage).

Does having a 2 die board mean I can only use one? Is it possible to access both chips and have 1Gb dram?

what changes have to be made for this?

[b36401]

You need to calibrate the board configured for both DDR chips and then use these calibrations.

[sujay1]

Can you please elaborate how to do this?

[b36401]

Here is a document regarding to DDR calibration:
https://community.nxp.com/docs/DOC-105652