A few of my friends and I are on F1 Visa and had to file our 1040NR and 540NR tax return forms.
We used the e-file option at https://www.ftb.ca.gov/ to file our state tax and it had generated a 540 form which we submitted online. We have also received our refund correctly.
Later we found out that F1 students weren't supposed to use e-file and are supposed to file a 540NR by postal mail.
Our situation right now is that we have filed a 540 instead of 540NR but do not have to get an extra refund or pay them back.
Do we have to file an 540NR with a 540X again? And if we should, would we be amending a 540 or a 540NR on the 540X?
Edit: 2013 was our first year here and we've been in the state for less than 6 months.