I solved this. Just reporting back for future users with same issue.
I used this Sun Oracle F80 800GB PCIe Flash Accelerator 7069200 - Fixing Incorrect Drive Capacity as a resource and looked at the edited bin file used for F80.
I used HxD hex editor on windows to edit the bin file. HxD was easier to delete and save compared to Ghex in linux (maybe user dependent…)
There are two locations for 000000EA 5AA5FA5A in the original bin file. Start from the first location and save as split.bin from original F40 firmware.