Non-Accessible Recovery Mode on Mac
Actually, I do not believe you need to enter what you refer to as Recovery Mode. If you the format either the 2nd, 3rd or 4th partition as MS-DOS(FAT), the partition method should change to hybrid.

You probably will not be able to install Windows 10 using a EFI boot method. You should use the legacy BIOS boot method. This means you want to use a hybrid partitioning scheme.

You should be able to download the "Boot Camp Support Software" (BCSS) using the Boot Camp Assistant. Although, for some Macs this download is the same as for a Windows 7 installation.

When running the Windows installer, you will need to reformat the MS-DOS(FAT) volume as NTFS.