I discovered that, finally, in the beginning of 2020, somebody implemented an untethered jailbreak for the ATV3 (https://kubadownload.com/news/jailbreak-apple-tv-3). I tested it, and it works indeed, with iOS 8.4.3 (not the latest version, but a version still signed by Apple).
I installed PlexConnect on it, but this is inferior even to the light Infuse version which was included in ATV flash black at the time. And , the ATV flash black installer is not fully working (it does install “Maintenance”, but not infuse), as we can expect.
Wouldn’t it be a great idea to adapt ATVflach black for the ATV3 too? I understand there isn’t a big market for this, and that h265 is out, but if the amount of work stays reasonable, it would be such a relief to eventually have the ATV3 with a decent player on it.
Thanks in advance to look at it!