UK chip designer Imagination Technologies -- which is in dispute with Apple, its largest customer -- has put itself up for sale. Shares in the company more than halved in April when Imagination said that Apple was to stop using its technology. From a report: The firm was regarded as a leading light in Britain's burgeoning tech sector, but ran into trouble when the phones giant, by far its biggest customer, said it would no longer rely on it for graphics design. Apple accounts for more than half of Imagination's revenues and last year held takeover talks with Imagination. Two parts of the business, MIPS and Ensigma, were already up for sale. Imagination said it has received "interest from a number of parties for a potential acquisition of the whole group." It is in "preliminary discussions" with the aid of bankers from Rothschild.