Troubled US vendor Motorola has bought half of mobile user interface company UIQ, going into joint ownership of the firm with Sony Ericsson.

Sony Ericsson bought the Swedish software firm UIQ Technology from Symbian, for an undisclosed sum in November last year.

Under the agreement, announced Monday, Motorola and Sony Ericsson will work together and jointly invest in the development of the UIQ open user interface platform.

But the move will raise a few eyebrows. At the time of Sony Ericsson’s acquisition of UIQ, it was understood that Motorola would no longer be supporting UIQ. Given that BenQ had dropped off the radar and Sendo had become part of Moto, it looked like Sony Ericsson was the only potential customer of UIQ left, making sense for the firm to absorb UIQ.

Both Sony Ericsson and Moto have agreed that UIQ will be vendor and chipset independent. In addition, UIQ will be licensed on equal terms to all mobile device vendors in the industry.

And what’s more, Sony Ericsson and Motorola are committed to expanding the shareholder base of UIQ to include other handset vendors. 

Alain Mutricy, senior vice president of Platforms at Motorola Mobile Devices, said: “Motorola’s investment in UIQ will enable us to bring feature-competitive multimedia devices to market. Its flexibility will enable us to bring devices to market that meet regional preferences or specific operator customisation requirements.”