I have iPhone 3GS, it is one of the old models, non-MC, model: MB715LL. I was able to tether with BenM hack under 3.0 however as soon as I heard my employer was giving out aircards I upgraded to 3.1.3 but instead of an aircard we got new laptop with integrated CDMA modem running on Sprint EVDO Rev A network. So basically I lost flexibility to tether my personal computers. I read on Redmond Pie that sn0wbreez can jailbreak 3.1.3 but have to be non-MC model, which I have. However my boot ROM is 05.12.01. So I would like to know if jailbreak is possible to enable tethering. Is the model has to be non-MC and boot ROM has to be older version or as long as its non-MC model, one should be able to jailbreak 3GS on 3.1.3?