Use APKPure App
Get Eject SD old version APK for Android
mount / umount SD card App Widget.
After install, register Widget to desktop.
Probably Android 4.0 cannot support(EjectSD4).
LG Optimus 2X : /mnt/emmc
Galaxy Tab : /mnt/sdcard/external_sd
Xoom/Xoom2 : /mnt/external1