Booting Linux file system from SD and enable partition VC707-U500

[jalezeta]

Hello, I am have just booted Linux in the freedom U500 implemented in the VC707 FPGA. I could login correctly, but now I would like to go a step further and be able to load Linux Root File System from the SD card. I have read that the Root File System was initially being loaded from the PCI Ethernet port, but I have implemented the non-PCI version and I would like to know if there is another way of doing it. I have followed the getting started guide by Sifive and I have loaded just the bbl.bin file through the command:
dd if=work/bbl.bin of=/dev/your-sd-card bs=1M

I was confused because this file is just 16MB, but apparently it works. On top of that, is there any support for loading the Linux Root File system from an SD partition?