apt-get update returns error

[deHakkelaar]

My mirror now is as clean as can be.

Try play with:
dpkg --print-architecture
dpkg --print-foreign-architectures

I believe with below one you can remove arch:
dpkg --remove-architecture i386

Or add :
dpkg --add-architecture armhf

Need to do 'apt-get update' afterwards and maybe 'apt-get clean' first.