As I understand it, it works. A hardware mod is more convenient though, since it stays through FW upgrades - which usually come rather frequently from Oppo. The FW hack needs to be done for each FW revision, easy if Oppo continues with the same internal structure and doesn't try to "fight" the hack, otherwise harder.

HD621, G98DH, G68ADV, Bc Acoustiqe ACT A3, 5200C DSP33, NuForce Reference 9 monoblocks, 2x SB3's, Velodyne DD-15 & DD-12 Subwoofers and a Meridian sub.