Mine turn green one time but didn't work.. i turn off the ps3 and did the process again with the LED still in green and it work.. Try renaming the file to psn_payload.bin and put it in the root and in the opt\psfreedom\payload folder and use the command Pillum put in his post: "cat psn_payload.bin > /proc/psfreedom/payload".

Also be sure your typing the command with the PSFreedom GUI open and the PL3 Mode selected. The command will show no output.