The current BDF targets the E-grade Xilinx device. The bitstream generated using that BDF will work on either the C-grade Ultra96-V2 (with E-grade ZU+) or the the I-grade Ultra96-V2 (with I-grade ZU+). However, just because it works does not mean that it is recommended that you do that. I am currently doing some additional research to figure out what the best practice is for supporting both the -E and -I ZU+ devices with our BDF.
You could try changing the target device to the -I after you use the BDF. I will be trying that myself in the next few days.