Good Morning, You may have missed part of what I have mentioned.... It works with jLog and KB (both linux based). Neither of these programs use the HAMLIB for radio control. I do have to use a script to set the com port for jLog. KB does it right! The author of KB wrote the script for me.
With your commands I have this: ls -l /dev/ttyUSB1 crw-rw---- 1 root uucp 188, 1 2008-01-26 16:57 /dev/ttyUSB1 groups users uucp dialout video
The radio does have v6 firmware. I have used it with DX4WIN, DXLab Suite, N1MM TR, CT, NA, Writelog, LogPlus, jLog (Windows & Linux), and many others. I know the that cable works.
I have learned that there are some very specific com port requirement setting for the Yaesu radios. I have confirmed this in the FT1000. I will look at the command that Stephane has suggested.