[Fire TV General] Pachacouti:
Ok, I'll try keep this as short as poss. First, I have never actually said your app is the problem. That done with, allow me:

Woke up one morning, plugged in firestick, it booted to just passed the BLACK Fire initial screen. It did not go to the 2nd screen, the blinding firetv logo, I guess this is animated.. at this point I was only using r_box's initial 6.2.7.1 with markus launcher, and new settings, which I marked as 1.03 (about 10 months old now). So I try to reflash r_box's again, no go. It would not boot past the 2nd screen, the animation logo, in fact, it black screened. When it initially died, I could still see it sending/receiving through my tomato router. So I decide to load up the latest 7.7. This worked, and I installed the origional launcher from 8 months ago, but had lost the newsettings.apk, which was 1.03 at that time, so I grabbed the one from this thread and the old launcher worked, at least, for 4 reboots of my 4k. Next day, same problem, no choice but to kamakiri/fireiso, tried going back to r_box's 7.1, no joy, tried 7.7 after that, no joy, so try's 7.3, and voila, it booted past the problem screen, only this time, it downloaded 3 full updates before I could login to wifi, the updates took my os to 6.2.7.6, which I thought was strange, but hey, I'm in. So this time, I solely disable the amazon launcher, and used the system settings to go to my apps and ran them from there, but again, next morning after a nice buffer free tv night, same thing, plugged it in, it would not go to 2nd screen. so back to fireiso, I attempt to go back to 7.3, same result, it black screened. I try every version up to 7.7, on 7.6, I thought I'd cracked it when I saw a breif glimpse of the white firetv screen, but it then again, blacked out. I have been unable to get passed this problem ever since.

It has occurred to me that perhaps amazon are using magisk against us, as I wiped the cache, dalvik, data, /system, and the fastboot userdata, yet no matter what I did, or do, I get as far as the 1st fire screen, and cannot get passed it. I reckon whatever they are doing, they are writing something to say boot.img, (I remember boot.img can be told not to boot past certain versions, wether this is true for the firestick?) or elsewhere, and all I'd really like is to obviously wipe all there is to wipe in order to load up a stock that works... No downgrade seems possible now.

When this problem started, I noticed an etra-ordinary jitter/buffering the night before, and put that down to the weather, now I'm not so sure. The thing is, I had deleted the amazon account I used origionally, just to see how long the firestick would work without an actuall account with amazon, well, I got about a year lol... I made a new one, after the initial crash forced me to pflash 7.3, which updated itself to 7.6, now I'm in the uk, so wonder if perhaps I cant go higher, because it aint out here yet?

Edit, I only flashed your zip once, after logging in to amazon. After that was getting a firmware to boot.

Edit 2: I had origionally posted in the unbrick fire thread : https://xdaforums.com/t/unbrick-fire-tv-stick-4k-help.4021923/page-4

Notice this.. same problem, for other users, include the fact I can no longer downgrade, makes me think others will arrive soon...