DDR vs DDR2

I have running uClinux on a board with DDR Rams. Our new design uses DDR2 Rams, DDR2 Rams only support burstlength 4 and not 2 as I used with the DDR Rams. I updated the burstlength in SOPC builder from 2 to 4, but after changing this Linux did not boot. Does anybody know if burstlength of 4 is supported.