Merge pull request #215 from nicola-masarone/patch-1

Update rpi-os.md

Author: s-matyukevich

docs/lesson01/rpi-os.md

@@ -484,7 +484,7 @@ Note that the sequence of steps described above asumes that you have Raspbian in
 1. Prepare your SD card:
     * Use an MBR partition table
     * Format the boot partition as FAT32
-    > The card should be formatted exactly in the same way as it is required to install Raspbian. Check `HOW TO FORMAT AN SD CARD AS FAT` section in the [official documenation](https://www.raspberrypi.org/documentation/installation/noobs.md) for more information.
+    > The card should be formatted exactly in the same way as it is required to install Raspbian. Check `HOW TO FORMAT AN SD CARD AS FAT` section in the [official documentation](https://www.raspberrypi.org/documentation/installation/noobs.md) for more information.
 1. Copy the following files to the card:
     * [bootcode.bin](https://github.com/raspberrypi/firmware/blob/master/boot/bootcode.bin) This is the GPU bootloader, it contains the GPU code to start the GPU and load the GPU firmware. 
     * [start.elf](https://github.com/raspberrypi/firmware/blob/master/boot/start.elf) This is the GPU firmware. It reads `config.txt` and enables the GPU to load and run ARM specific user code from `kernel8.img`