Hello,
I am having the same problem as the original poster. Following the link you provided doesn't help, like what GregD told you, the BSP Editor is no longer available in later versions, and the u-boot flow has changed (instead of having one .bin file for the whole uboot, now we have 2 files : spl/u-boot-splx4.sfp to put on the A2 type partition of the emmc, and the u-boot.img to put into the fat type partition). Which one should be used to be converted into the hex file? And how? Using objcopy on these ones will create big hex files!
What happened to this boot HPS from FPGA method? Did Intel decide to not support this method anymore, leaving customers in difficulty?