Hi there!
Per our upgrade guide at https://library.netapp.com/ecm/ecm_download_file/ECMP1368868, upgrades are only supported from 8.1.x to 8.2.x and upgrading from 8.0.x to 8.2.x, you must make an intermediate upgrade to 8.1 first.
As you've noticed however, 8.1 is past our self-support date and has been removed from our site for download.
Complicating things, you can't even re-install as 8.2 as we use different license keys between 8.1 and 8.2, and the FAS3270 has been End of Support Life for a while, so you probably can't get 8.2 licenses issued for it.
Unfortunately we are unable to assist further.