rhs.hk worked for me, but expect the tracking number you get from them to not work for weeks.
(I imagine rhs.com is faster, but they actually charge for shipping...)
Figured it out. I got lucky.
On http://www.ezflash.cn/downloads/ there's this file: http://www.ezflash.cn/zip/EZ4_2014.rar
(Note that it's .rar, not .zip; the .zip file contains different stuff for some reason)
The file should contain 3 files: an EZ4_Client.exe from 2006 and two .bin files...
only ps5 updated to latest firmware can go on psn, jailbroken ones just don't use psn or they risk getting flagged or banned, altho spouting profanity in online play alredy does that