android/grapheneos: added comparison and backup

wiki/android.md

@@ -96,13 +96,16 @@ This app is available at [F-Droid](/wiki/android/f-droid.md) as
 [Google Play Store](#app-store) by the
 [same name](https://f-droid.org/de/packages/org.liberty.android.freeotpplus/).
 
-### Custom ROMs
+### Android-based Operating Systems
 
-Besides the stock-firmware of vendors there are also custom ROMs.
+Besides the stock-firmware of vendors there are also so called custom ROMs.
 These are alternative firmware variants made by third party providers.
 Well known custom ROMs [LineageOS](/wiki/android/lineageos.md) and
 [GrapheneOS](/wiki/android/grapheneos.md).
 
+A general comparison of different operating systems based on Android can be found in a
+[table by eylenburg](https://eylenburg.github.io/android_comparison.htm).
+
 It is possible that some custom ROMs require the user to
 [unlock the bootloader](#unlocking-the-bootloader) before the installation can happen.
 

wiki/android/grapheneos.md

@@ -21,3 +21,12 @@ This section addresses the usage of GrapheneOS.
 GrapheneOS features various settings and possibilities for configurations.
 A general overview of this was give in a
 [Reddit post by Tryptamine9](https://www.reddit.com/r/GrapheneOS/comments/18te8no/my_ride_through_grapheneos_what_works_and_guide/).
+Another recommendation on settings for GrapheneOS can be found in 
+[a post by ventral digital](https://ventral.digital/posts/2024/12/9/practical-grapheneos-for-the-paranoid/).
+
+### Backup
+
+GrapheneOS features a built-in backup utility.
+It can be found in the settings under `System` and `Backup`.
+When enabled a recovery code made up by mutliple words have to be stored to be able to restore the
+backed up data.