[HTC Sensation] Mercvtio:
Don't know if it can help, but I ran a logcat while turning tethering on and connecting my tablet. A bunch of red lines came up concerning tethering. I'm no programmer, and I understand close to nothing in what it says, but I'll put it here, just in case you can do something with it :

10-21 15:48:51.765 D/Tethering(353): InitialState.processMessage what=4
10-21 15:48:51.765 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:48:53.487 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:48:53.487 D/Tethering(353): InitialState.processMessage what=4
10-21 15:48:53.487 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:48:54.177 D/Tethering(353): sendTetherStateChangedBroadcast 1, 0, 0
10-21 15:48:54.318 D/Tethering(353): Tethering wlan0
10-21 15:48:54.318 D/Tethering(353): InitialState.processMessage what=2
10-21 15:48:54.318 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:48:54.318 D/Tethering(353): Tethered wlan0
10-21 15:48:54.318 D/Tethering(353): sendTetherStateChangedBroadcast 0, 1, 0
10-21 15:48:54.338 D/Tethering(353): MasterInitialState.processMessage what=1
10-21 15:48:54.338 D/TetherController(138): Starting tethering services
10-21 15:48:54.338 D/TetherController(138): Tethering services running
10-21 15:48:54.338 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:48:54.388 D/Tethering(353): notifying tethered with iface =null
10-21 15:48:54.388 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:48:58.762 D/Tethering(353): TetherModeAliveState.processMessage what=3
10-21 15:48:58.762 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:48:58.802 D/Tethering(353): notifying tethered with iface =null
10-21 15:48:58.802 D/Tethering(353): TetherModeAliveState.processMessage what=3
10-21 15:48:58.802 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:48:58.802 D/Tethering(353): notifying tethered with iface =null
10-21 15:48:58.802 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:48:58.802 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:49:34.427 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:49:38.821 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:49:38.821 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:49:42.134 D/Tethering(353): Untethering wlan0
10-21 15:49:42.144 D/Tethering(353): TetheredState.processMessage what=3
10-21 15:49:42.144 D/Tethering(353): Untethered wlan0
10-21 15:49:42.144 D/Tethering(353): sendTetherStateChangedBroadcast 1, 0, 0
10-21 15:49:42.164 D/Tethering(353): TetherModeAliveState.processMessage what=2
10-21 15:49:42.905 D/TetherController(138): Stopping tethering services
10-21 15:49:42.905 D/TetherController(138): Tethering services stopped
10-21 15:49:42.945 D/Tethering(353): notifying tethered with iface =null
10-21 15:49:42.945 D/Tethering(353): InitialState.processMessage what=4
10-21 15:49:42.945 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:49:44.266 D/Tethering(353): sendTetherStateChangedBroadcast 1, 0, 0
10-21 15:49:44.276 D/Tethering(353): InitialState.processMessage what=4
10-21 15:49:44.276 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:49:44.987 D/Tethering(353): sendTetherStateChangedBroadcast 1, 0, 0
10-21 15:49:45.127 D/Tethering(353): Tethering wlan0
10-21 15:49:45.127 D/Tethering(353): InitialState.processMessage what=2
10-21 15:49:45.127 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:49:45.127 D/Tethering(353): Tethered wlan0
10-21 15:49:45.127 D/Tethering(353): sendTetherStateChangedBroadcast 0, 1, 0
10-21 15:49:45.137 D/Tethering(353): MasterInitialState.processMessage what=1
10-21 15:49:45.147 D/TetherController(138): Starting tethering services
10-21 15:49:45.147 D/TetherController(138): Tethering services running
10-21 15:49:45.157 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:49:45.197 D/Tethering(353): notifying tethered with iface =null
10-21 15:49:45.197 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:49:49.692 D/Tethering(353): TetherModeAliveState.processMessage what=3
10-21 15:49:49.692 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:49:49.702 D/Tethering(353): notifying tethered with iface =null
10-21 15:49:49.702 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:49:49.722 D/Tethering(353): TetherModeAliveState.processMessage what=3
10-21 15:49:49.722 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:49:49.722 D/Tethering(353): notifying tethered with iface =null
10-21 15:49:49.722 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:50:18.860 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:50:25.196 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:50:29.701 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:50:29.721 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:51:09.770 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:51:49.819 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:51:55.224 D/Tethering(353): Untethering wlan0
10-21 15:51:55.224 D/Tethering(353): TetheredState.processMessage what=3
10-21 15:51:55.224 D/Tethering(353): Untethered wlan0
10-21 15:51:55.224 D/Tethering(353): sendTetherStateChangedBroadcast 1, 0, 0
10-21 15:51:55.224 D/Tethering(353): TetherModeAliveState.processMessage what=2
10-21 15:51:55.224 D/TetherController(138): Stopping tethering services
10-21 15:51:55.224 D/TetherController(138): Tethering services stopped
10-21 15:51:55.244 D/Tethering(353): notifying tethered with iface =null
10-21 15:51:55.484 D/Tethering(353): InitialState.processMessage what=4
10-21 15:51:55.484 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:52:06.955 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:52:06.955 D/Tethering(353): InitialState.processMessage what=4
10-21 15:52:06.955 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:52:07.676 D/Tethering(353): sendTetherStateChangedBroadcast 1, 0, 0
10-21 15:52:07.786 D/Tethering(353): Tethering wlan0
10-21 15:52:07.786 D/Tethering(353): InitialState.processMessage what=2
10-21 15:52:07.786 D/Tethering(353): sendTetherStateChangedBroadcast 0, 0, 0
10-21 15:52:07.796 D/Tethering(353): Tethered wlan0
10-21 15:52:07.806 D/Tethering(353): sendTetherStateChangedBroadcast 0, 1, 0
10-21 15:52:07.816 D/Tethering(353): MasterInitialState.processMessage what=1
10-21 15:52:07.826 D/TetherController(138): Starting tethering services
10-21 15:52:07.826 D/TetherController(138): Tethering services running
10-21 15:52:07.846 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:52:07.866 D/Tethering(353): notifying tethered with iface =null
10-21 15:52:07.866 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:52:12.331 D/Tethering(353): TetherModeAliveState.processMessage what=3
10-21 15:52:12.331 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:52:12.341 D/Tethering(353): notifying tethered with iface =null
10-21 15:52:12.341 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:52:12.351 D/Tethering(353): TetherModeAliveState.processMessage what=3
10-21 15:52:12.351 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:52:12.361 D/Tethering(353): notifying tethered with iface =null
10-21 15:52:12.361 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:52:29.838 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:52:47.895 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:52:52.350 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:52:52.360 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:53:32.409 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:54:12.458 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:54:52.507 D/Tethering(353): TetherModeAliveState.processMessage what=4
10-21 15:55:24.138 D/Tethering(353): TetherModeAliveState.processMessage what=3
10-21 15:55:24.138 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:55:24.168 D/Tethering(353): notifying tethered with iface =null
10-21 15:55:24.168 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:55:31.745 D/Tethering(353): TetherModeAliveState.processMessage what=3
10-21 15:55:31.755 D/Tethering(353): chooseUpstreamType(true), preferredApn =4, got type=-1
10-21 15:55:31.785 D/Tethering(353): notifying tethered with iface =null
10-21 15:55:31.785 D/Tethering(353): TetheredState.processMessage what=12
10-21 15:55:32.516 D/Tethering(353): TetherModeAliveState.processMessage what=4