How to solve "Host filesystem not supported when direct drivers are used"?.

I want to use the generic serial flash interface to access the configure flash ROM and use a JTAG cable to read the data to PC host and save it to PC.

The source code about file access is :

FILE *fp=NULL;

fp = fopen("/mnt/host/epcql256.bin", "w");

fclose(fp);

I checked the hal.enable_small_c_library and hal.enable_reduced_device_drivers .

When I compile the program , it has a error

"Error: Host filesystem not supported when direct drivers are used."

If I don't check hal.enable_small_c_library , the error is "address 0x201f324 of gflish.elf section `.rwdata' is not within region `main_memory" , the device is arria10 10AS048H4F34E3SG , it has not enough memory to address 0x201f324 .

How can I use a indirect driver ?

Thanks