There are also versions that turn the IDE header into 2 SATA ports (which the TiVo sees as IDE master and slave). The SunPlus and JMicron chipsets will most likely not work in an S1--they're much more finicky than S2s. S1s--use a Marvell chipset. S2s--use a Marvell or JMicron chipset In a computer, either of the above, but don't be surprised if a SunPlus chipset is iffy at best. If you got that thing with the no-name chipset to work in an S1, you really lucked out. Maybe those are Marvell chips that failed QC, so they sold them unbranded.