The latest firmware update for Sony's PlayStation Vita introduces a new, unadvertised restriction: the system now locks Vita memory cards to a single PlayStation Network account. That's a new inconvenience for Vita owners who may have signed up for multiple PSN accounts to access the PlayStation Store in other regions.

Prior to firmware 1.80, Vita owners had the option to purchase and store content from multiple regions on a single memory card. Although switching between PlayStation Network accounts on the Vita was clumsy — a multi-step process that required "restoring" one's Vita — it let users enjoy games available from Japan, North America, and Europe on a single memory card.

The newest system update, released earlier this week, now requires Vita owners to format their memory cards if they switch accounts. The solution? Buy another Vita memory card.

That's an especially painful change for Vita owners in the wake of the system's newly added support for original PlayStation games. While the European PlayStation Store boasts 129 PSone Classics and the Japanese version more than 200, the North American PlayStation Store offers just nine for download. Vita owners have been using a workaround to get PSone Classics previously purchased on the PlayStation 3 to their Vitas, but it's still a much smaller list.

Polygon has contacted Sony Computer Entertainment America reps seeking clarification on the change, but the company has not yet responded. We'll update if they do.