If you are looking for a flash file system to run on a FL01GS then I would recommend JFFS2. If the two dies of the package shall appear as one single partition then we can give you some mtdconcat glue code to create one single MTD over the two dies.
FAT can also be run on it but we do not recommend that. You would have to run the FTL driver on top of the chips, then VFAT. It is all included in the standard Linux kernel.
Thank you and have a wonderful day