Sony America has said that it will not be possible for people to exchange their UMDs for digital versions of the games they own.
"We were evaluating a UMD conversion programme, but due to legal and technical reasons we will not be offering the programme at this time," a spokesman told Kotaku.
The idea would have been to hand in your UMD copy of, say, Lumines, and receive a digital copy of the same game in return.
In Europe, at least, Sony is offering people who upgrade to PSPgo the choice of three free digital downloads, providing they own at least one UMD game.
There are 17 titles to choose from, including Echochrome, LocoRoco, Patapon, Resistance: Retribution and WipEout Pure.