we don’t make ‘ready’ images for this configuration, but I have tested it sometime ago, e.g. 32-bit (armhf) debian running on DB410c, using the 64-bit kernel. Running 32-bit kernel is not something we support (nor plan to support).
To run armhf debian you will need to make/build your own image. You can potentially start from the Debian image we make for Snapdragon 600 (APQ8064) , see http://releases.linaro.org/debian/boards/snapdragon/latest/. These images are built exactly like the DB410c images, but for the IFC6410 (and other 8064 based boards).
There aren’t so many differences between the 2 images, and you can check how we build them by looking at these 2 scripts:
Alternatively, you can start from scratch (debootstrap) too, but that means you are familiar with this tool.
If you have any issue, please post them here.