Hello !
The problem could be the "minix" version. There are two minix
fs out in the world. One is called Old-Minix in Linux's fdisk,
supporting up to 14 characters file names and up to 64MB (AFAIK).
The new minix file system has much larger limits (256 char names,
etc...).
I don't know exactly,
After reading the article in the recent edition of the Linux Journal, I
decided to take a look at grub. I had no problems with building grub
and found that grub worked well with ext2 file systems and fat16 file
systems. However, I discovered that grub could not recognize a minix
file system.