Question: I have a Raspberry Pi 1 running Raspbian. I tried running the SD card from it on a Raspberry Pi 3 but it didn't boot.

I've read various things about upgrading a Raspberry Pi 2 install to run on Raspberry Pi 3, but little for upgrading from 1 to 3.

Can anyone please help?

Answer: 
All you need to do is update the firmware of your raspberry Pi while the sd card is still plugged in your RPi 1,

* Step 1, Update the System, `sudo apt-get update`
* Step 2, Upgrade the System `sudo apt-get upgrade`
* Step 3, Update the firmware itself, `sudo apt-get install rpi-update`

Reboot and shutdown your RPi 1.

These two links might be helpful for troubleshooting,

* [Update the Firmware on a Raspberry Pi](https://linhost.info/2015/05/update-the-firmware-on-a-raspberry-pi/)
* [Pi 3 cannot boot images
that for with Pi 2?](https://www.raspberrypi.org/forums/viewtopic.php?t=138725&p=926016)
**The OS for Raspberry Pi 1 is mainly the same as Pi 3,**
so you should be able to install the software for this transfer.

Put NOOBS on the Pi 1's SD and boot. Find the "edit config" area and change the OS to Pi3

First, find a USB to MicroSD card adapter (found on Amazon for dirt cheap). Plug in the Pi 3's SD Card and choose it as the copy to device. Choose the Pi 1's SD as the source, then begin the copy. This can take up to 30 minutes. Next, safely eject the Pi 3's SD Card and format the Pi 1's SD. Next, insert the SDCard into your Pi 3 and boot.

*You now have Raspbian Full on the Pi 3.*