Metricom Inc. investor Paul Allen agreed to boost his stake in the company to 49%, solidifying the Microsoft Corp. co-founder's hold on the wireless data-services provider. Allen's Vulcan Ventures Inc. investment company said it will buy 4.65 million Metricom shares for $56 million and, in a separate transaction, agreed to buy an additional 2.58 million shares from the Lindner Group for an undisclosed amount. The two purchases would raise Vulcan's stake to 49%. Los Gatos-based Metricom is developing technology to allow computer users to get wireless Internet access about five times faster than current wireless networks allow. Metricom shares rose $1.88 to close at $14.75 on Nasdaq.