I don't understand what you are asking. read my first post which explains how to downgrade the remote. you may not need the gs_ofdm.bin since you can do the force reinstall trick on the remote from the video above... so all you need to do is put it into force reinstall mode, then rename the 1.5.7 bin to old or whatever you want and then rename the firmware you want to what the 1.5.7 bin was called... on ios devices the firmware files are in fmdir you need a jailbroken or rooted device to modify system/app/hidden files
one other thing I should point out is that I was unable to go from 1.4.3 to 1.1.9, I had to go down to 1.3.2 then 1.1.9. I also couldn't go from 1.3.2 to 1.1.8, but I was able to flash 1.1.8 after I had 1.1.9 on the radio (this could likely be due to the way I did it, perhaps there is a way to go directly from 1.4.3 to 1.1.9 or whatever, but I couldn't in my case). The light was green and it seemed like it went through, but the DJI go app still said 1.1.9, likely because dji go will recognize anything below 1.1.9 as 1.1.9 anyway...