A method in a computer system for performing a data transfer between a first data processing device (1) and a second data processing device (2) comprises providing a downloading process (10) configured for downloading of data (120) from the first data processing device (1) to the second data processing device (2) via a connection between the first data processing device (1) and the second data processing device (2) Further, the method comprises providing at least one download parameter (101-111) for the downloading of the data (120), the down load parameter containing information for indicating a downloading destination (8, 81) on the second data processing device (2), and providing a loader data file (5) as an input to the downloading process (10), the loader data file including the at least one download parameter (101-111) and the data (120) to be downloaded.