you won't be able to use the captivate on boost mobile. boost mobile is a subsidiary of sprint/nextel and uses CDMA/iDEN technology. you must use one of their phones (CDMA/iDEN compatible ones)... a GSM phone like the Captivate will *not* work on their service.
as for the rest of your issues, the phone must be rooted and have busybox installed (which will not work when stock).
Samsung Captivate | Google Galaxy Nexus (GSM) | Google Nexus 7 (2012) | LG Optimus G (E970)
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