The US Court of Appeal for the Federal Circuit in Washington DC upheld patent holding company NTP’s claim that RIM infringed a number of patents it owns relating to wireless email. But perceived flaws in last year’s ruling from the US District Court for the Eastern District of Virginia halting BlackBerry sales in the US mean the case has been returned to a lower court for a final hearing.

The general consensus on Wall Street is that the hearing will once again favor NTP, forcing RIM to either reach a settlement or cease selling its BlackBerry system in its biggest market. NTP is thought be pushing for the latter, although it is thought likely to accept ongoing royalty payments as compensation. RIM has already paid out tens of millions of dollars to NTP in compensation.

NTP’s claim is centered on software developed by engineers in Chicago in 1990 but never commercialized. Thomas Campana, the key engineer on the project, died on June 8 this year, the day after RIM’s appeal against the original injunction started.