Nevermind, I got the jailbreak working on my PW6 running 15.8.5.0.1.
I appended the following line to the offsets definitions in adbreak.html:
Code:
'455680': { memcpy_got: 0xbe4ac, xml_got: 0xbebd8, memcpy_offset: 0x94c00, system_offset: 0x42938 }, // fs_update_kindle_all_new_paperwhite_12th_5.18.5.0.1
I got the '455680' from the popup when I ran the original jailbreak on 15.8.5.0.1, and copied everything else from the 15.8.5 firmware. Those addresses didn't change between 15.8.4 and 15.8.4.0.1, so I figured maybe they didn't change for 15.8.5.0.1 either.
It worked for me, but DYODD and all that.