How to make Android always use external SD card instead of internal storage?
/sdcard isn't physically external SD card but a symlink to primary external shared storage. See details in my answers to Android's Storage Journey and What is /storage/emulated/0/?
From your comment:

How can make Android use the 2GB device instead of the smaller one. How do I configure this?

Android by-default doesn't use secondary external shared storage. But apps can, if they want. See my answer to How to save files to external SD card on a non-rooted Android?.
If you want to make Android always use physical SD card as primary external shared storage, you need to change your ROM's configuration from Emulated primary only or Emulated primary, physical secondary to Physical primary only. It's possible by editing the fstab file and some init's .rc file. Follow the above official documentation links for details on configuration changes.