Issue with erasing ROMS partition

[bluest2]

Hi, firstly, thank you for providing this guide. I have an issue when I erase the ROMS partition in Disk Utility the operation fails with the following message:

_Erasing "ROMS" (disk6s4) and creating "ROMS"

Unmounting disk Mediakit reports not enough space on device for requested operation.: (-5344)

Operation failed..._

I notice that my ROMS partition size is much larger than in the example in your tutorial and in fact the combined size of ROMS and MISC partitions is a little larger than the total SD card capacity (64GB card).