diff --git a/how_to b/how_to
index 7594636..7eca7f8 100644
--- a/how_to
+++ b/how_to
@@ -872,6 +872,25 @@ Android:
         # https://toot.party/@SigmaOne/106159205703917847
         Custom NotoColorEmoji.ttf in /system/fonts/
 
+    Make SIP call from the default phone app:
+        # https://shkspr.mobi/blog/2020/07/adding-sip-calls-to-android-for-free/
+        Phone > Settings > Call Settings > SIP accounts
+
+    Rip an ebook (or any paginated document) from android (quick and dirty):
+        # By Terence Eden
+        # https://shkspr.mobi/blog/2021/12/quick-and-dirty-way-to-rip-an-ebook-from-android/
+        screenshot script:
+            #!/bin/bash
+            for i in {00001..00555}; do
+               adb exec-out screencap -p > $i.png
+               adb shell input tap 1000 2000
+               sleep 1s
+            done
+            echo All done
+
+        Use mogrify to crop and trim as needed.
+        Use pdfsandwich or ocrmypdf to add OCR info.
+
 Fix: Failed to activate service 'org.freedesktop.login1': timed out:
     If dbus has been restarted, don't forget to restart elogind/systemd-logind