Talk:TeraStation larger disks
From NAS-Central Buffalo - The Linkstation Wiki
you mentioned the ARM based TS in you article. To change the disks without any loss of data is described here http://buffalo.nas-central.org/index.php/Replacing_all_drives_in_a_Terastation_Live. I did it with my 2TB TS Live to an 4TB one without any problems a data loss.
May be it's useful to provide a link to the other article in the ARM part of yours.