Update README

README.md

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 # splash-imgs
-Build your own splash screens for the FP2
+Build your own splash screens for the Fairphone 2 (FP2)
+
+# Building the splash screen
+
+## Requirements
+
+- Python 2.7
+- PIL
+
+### Debian/Ubuntu
+
+Install `python` and `python-imaging` from your distro software repositories:
+
+```
+sudo apt install python python-imaging
+```
+
+## Build the splash screen
+
+Run:
+
+```
+python2 logo_gen.py <raster image file>
+```
+
+Raster image file can be PNG, JPEG, BMP and GIF, no bigger than 1080x1920 pixels (FP2's resolution)
+
+Splash image will be saved to `./splash.img`
+
+
+# Flashing the splash screen
+
+> WARNING: Do at your own risk. I won't take any responsibility if this action bricks or damage your phone, although that seems unlikely. See the [Restoring original image](#restoring-original-image) section if your image does not work as expected.
+
+## Requirements
+
+- Fastboot Android SDK tool
+
+### Debian/Ubuntu
+
+Install `fastboot` or `android-sdk-platform-tools` if you want `adb` too
+
+```
+apt install android-sdk-platform-tools
+```
+
+## Flash the splash screen
+
+Boot your Fairphone 2 in `fastboot` mode, either by `adb reboot bootloader` (if you installed `adb` too) or by holding `power down` while booting your Fairphone 2.
+
+Then run this command:
+```
+fastboot flash splash splash.img
+```
+
+Replace `splash.img` with the path to your splash screen, if other.
+
+
+### Restoring original image
+
+If your own splash screen didn't worked as expected, you can find official Fairphone 2 splash screens under the `official-splash-imgs` folder, here in the repo. `lp_splash.img` is the splash screen for Lollipop and `mm_splash.img` is the one for Marhsmallow. Take either file and flash it with the instructions provided above.