.If it voided the warranty, why would they have instructions how to do it in the user setup guide?
There are two DIMM sockets, one empty one on the outside of the logic board and one with a 1 GB module on the inside. Using a dental-like mirror, I found the sticker on that memory module to say warranty voided if removed or something like that. You'd probably have to remove the logic board from the stand-offs to be able to swap it from a 1 GB to a 2 GB to reach a total of 4 GB. I just put a 2 GB Crucial in the outside module for a total of 3 GB. I don't think my memory usage yet as even come close to 512 MB, but it has exceeded 256 a time or two.
DS 1512+ w/3GB, 5 x 3TB Seagate ST3000DM001 8.2TB RAID 6, half files/half Time Machine.
Icy Dock MB559U3S-1SB enclosure w/4TB Hitachi UltraStar via USB 3 for files backup
UVERSE to AirPort Extreme + 2 AirPort Express w/speakers. TRENDnet TV-IP312WN camera
CyberPower CP1500PFCLCD Sine Wave UPS
DSM 4.1-2661 w/SSH + SFTP, VPN Server, Syslog Server, Media Server, Mail Server, Mail Station,
Audio Station, Surveillance Station, Photo Station, Web Station - DS Apps on iPad & iPod Touch.