add mobile docs

mobile/android-add-frida-gadget.md

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+
+## Get APK from device over adb
+
+find apk file on device:
+```
+adb shell
+pm list packages -f | grep -i <appname>
+```
+
+pull apk file from device:
+```
+adb pull <path>
+```
+
+## unpack and modify APK to add frida libgadget
+
+
+unpack apk with apktool:
+```
+apktool d -o unpack app.apk
+```
+
+download frida gadget native lib + extract and rename:
+```
+cd unpack/lib/arm64-v8a
+wget https://github.com/frida/frida/releases/download/16.1.5/frida-gadget-16.1.5-android-arm64.so.xz
+unxz frida-gadget-16.1.5-android-arm64.so.xz
+mv frida-gadget-16.1.5-android-arm64.so libfrida-gadget.so
+```
+
+find LAUNCHER activity in manifest:
+```
+TODO
+```
+
+search for LAUNCHER activity smali code:
+```
+TODO
+```
+
+look for the following method:
+```
+.method public constructor <init>()V
+```
+
+add the following smali code to the above constructor:
+```
+const-string v0, "frida-gadget"
+invoke-static {v0}, Ljava/lang/System;->loadLibrary(Ljava/lang/String;)V
+```
+
+
+add to manifest application element:
+```
+android:usesCleartextTraffic="true"
+android:extractNativeLibs="true"
+```
+
+## Generate a JKS for APK signing
+
+run keytool to generate java keystore (JKS) for apk signing:
+```
+keytool -genkey -v -keystore custom.keystore -alias mykeyaliasname -keyalg RSA -keysize 2048 -validity 10000
+```
+
+## Repackage APK
+
+repack APK:
+```
+apktool b --use-aapt2 -o mod-app.apk unpack/
+```
+
+zipalign APK:
+```
+zipalign 4 mod-app.apk final-mod-app.apk
+```
+
+sign APK file with JKS:
+```
+apksigner sign -ks custom.keystore final-mod-app.apk
+```
+
+## Install APK to phone
+
+install APK with adb:
+```
+adb install final-mod-app.apk
+```
+
+## Frida scripts for bypass pinning
+
+Sometimes one of these scripts will fail for some reason.
+
+frida ssl bypass scripts:
+```
+frida -U gadget --codeshare akabe1/frida-multiple-unpinning
+frida -U gadget --codeshare sowdust/universal-android-ssl-pinning-bypass-2
+```