My son has a Galaxy A40 and as the title states the phone is stuck at a blue screen that says "Downloading...Do not turn off target." Holding the power button down to turn off the phone from this screen does nothing. Holding the volume up and volume down plus power buttons at the same time will reboot the phone but it goes right back into this blue screen.
So I held the volume up and down plus power buttons again and when the phone reboots I hold the volume up and power buttons and it will boot to the Android avatar with a progress bar that always gets to 25% and then the word "error" flashes and the phone reboots to the blue screen. It does this every time. Never gets past 25%.
Many thanks to anyone who may be able to help!
My A5 2017 kept going to that blue screen about a month ago.
At first holding the power, volume down and home button at the same time for 7 seconds, then as soon as the screen goes black you release the buttons and it should reboot.
However after 2 weeks of this, eventually I could not get the phone to reboot and it just goes straight back to blue screen.
Volume down, power and home definitely works though.