If a lightning bolt image appears in the top-right corner of the screen, it means Raspberry Pi is not getting enough voltage (4.65V according to this forum post). To prevent it from showing up, there are two options.
1) Replace Power Supply and/or Cable (Recommended)
In most cases, it’s due to the power supply and/or cable. Replacing those with better one such as CanaKit 5V 2.5A Power Supply or HomeSpot 5V 2.4A Power Supply will most likely fix the problem. I like HomeSpot because it has ON/OFF switch, which is very convenient to power up Raspberry Pi.
2) Disable Under-voltage Warning (Not Recommended)
Under-voltage may cause SD card corruption and/or other problems. Disabling the warning won’t make it any better. But if you understand the risk, it can be disabled by the steps below. I tested it with Raspbian Stretch (November 2017 version).
Open /boot/config.txt file.
sudo nano /boot/config.txt
Add below, save and close the file.
# Disable under-voltage warning avoid_warnings=1
Reboot to apply the change.
sudo reboot
got new power supply, still not fixed
having the same problem even used a old apple i pad charger ( i think it probably has the best chance of giving the power it says it dos) and after one years found a chipped capacitor probably a bypass cap very small 1×0.5 ish mm smd cap and replaced it and it fixed it
Hey, I’m facing a similar issue with my Raspberry Pi (model 3), can you please share some schematics or info on how you found the damaged capacitor? Can it be tested with multimeter? I’ve tried several power supplies and cables which work well with Raspberry Pi 2 so I don’t think that is the issue. Thanks KP
I noticed this issue does not exist when I first installed Retropie on my raspberry pi 4, it only shows up after I update all the packages but I purchased this all as a kit and am using the cord they sent me with the same issue.
Not worth the value of having it on, I have tried all types of power supplies that at least provide the required current and it still keeps flashing away.
This message is a bug of new Raspian version. I have two pi 3 plus and this problems arrives when i did an update, with the two units. I measure the voltage at USB output and its 5.08 and 5.12, this this message is a softare bug. Don’t lost your money with a new suply/cable, it will NOT solve this boring message.
so which Raspian version is affected and which one solves it then?
Can confim, it must be a bug, measured 4.85V on the GPIO pins under maximum load (and overclocked slightly), 4.96V when idle. Warning still up.
VOLTAGE DROP caused by tiny wires in modern USB cables is (probably) the problem.
Change to an older (thicker) and much shorter cable to reduce losses.
bye.
I did that but after few days got that warning bolt again on my screen.
Nope, did not work for me. I have a R-Pi 4 8GB. Modified the config.txt file. Rebooted. ‘Low voltage warning’ pop-up came right back. Please, people, check your commands before posting on the internet. Seems like a lot of people are posting without checking.