Are you using or tried the sd from the other pi?
Yup, both SD's work in "other pi, neither SD's work in the + one...
5 of 5 people found this helpful
Ok so what I would is make sure you power is 5v 3amp and then try a new image from https://www.raspberrypi.org/downloads/raspbian/ try that and see if it will work if that dosen't work and you are still unable to boot past that part you could also try https://berryterminal.com/doku.php/berryboot since its a pure drop and drag not need to use etcher or any other img software.
Also make sure no other hardware is plugged in besides hdmi and power for testing.
If still nothing try another power supply and make sure plugging directly into the wall and not into a power bar.
Also if you can take a close up of the sd card slot make sure no pins are damaged.
hopefully something above helps you out a bit or give you something new to try.
3 of 3 people found this helpful
Sounds like your software is not up-to-date and doesn't have support for the 3B+ yet.
While the SD card is in a different Pi:
sudo apt-get update && sudo apt-get dist-upgrade -y sudo rpi-update
That will update the software and firmware. The card should then work in your 3B+.
OK, I'm an idiot... What do I do from the start-up screen before I type
sudo apt-get update && sudo apt-get dist-upgrade -y sudo rpi-update?
I would suggest to just reimage the SD with the latest version of Rasbian (if that is what you want to run). The hardware on the RasPi 3 B+ is different than a standard 3 so the drivers will be different and you could run into other issues down the road.
You can get the image from:
However, if the B+ came with a preloaded SD card, then I would ensure you inform the vendor you got the board from that the image on the SD card does not work with the B+.