so my roku 4 bricked, called customer no service support and they said get a new one in English the best they could. Somewhere in the back of my mind I thought I read the micro sd card was the problem now I couldn't find the power supply. Found the PS took out the micro SD and lo and behold it's working. Of course the first time I ran into this was a couple of years ago and it appears Roku didn't see fit to fix the issue OR tell their tech support about the problem with the Microsd cards. Instead it appears they were instructed to let the cuistomer know to purchase a new one. WHAT CRAP ROKU!
I had the same problem with and endless reboot. Incidentally, it started when I was watching- i pressed a key to change channels on the remote and that triggered the endless reboot. When I saw your post, I removed the sd card. It stopped the endless reboot- but that caused the screen to go black. I tried a reset with no change. Did a hard reset - still no change. Just to rule out other possibilities I removed the roku 4 and replaced it with an old roku 3. The 3 worked fine. Went back to the four and did resets with no change. I even reinserted the sd card. I have a permanent black screen ( the light still flashes on the roku 4 but otherwise it isn’t functioning. Any suggestions would be appreciated.
One would assume that you powered the ROKU off (unplugged) prior to removing the SD card and not while it was under power? I only ask because 6 months ago my 4 started that reboot nonsense too. So I unplugged it, removed the SD card, then powered it on and it's been fine ever since. Electronics take a very dim view of having their components removed while under power. Just saying.
ROKU Stick (2017) ROKU TVs (55S405 & 32S305) Express+ 2017 (3910RW) ROKU 4 (4400R)