Even on 2MB, you should be able to at least see GRUB, which would tell you that it can't load the kernel. Does it go blank before that? This could mean an issue with either GRUB or the floppy.
In case you have DOS installed on the hard drive, you can also use GRUB4DOS [1] - just put gentleos.elf on C:\, run grub.exe, then `kernel /gentleos.elf`. You may first need to comment out any upper memory managers from config.sys. A bit of an academic exercise since the kernel still won't fit into memory.
Btw. feel free to reach out to me on my profile email. I'll be busy with work for the rest of the week, but later I may look for some workarounds to get it running on 2 megs.