[HTC Sensation] Skipjacks:
5/19/2013 Update: The bug might be dead! Like for real this time. See this post, post number 14 in this thread with an explanation of what to do.

10/25/2012 Update: TRY THE LATEST BUILDS OF BRUCE'S CM10 STARTING WITH THE 10/25 VERSION!

Bruce has made a change that helps differentiate between the regular data stream and the MMS data stream in an attempt to see if that was what was causing the instability issue. This is only on Bruce's CM10 Kang as of 10/25. If you are only another CM ROM, flash Bruce's (even if just for a minute or two) and see if the data bug goes away. Please report back if it did!

If this does cure it, I'm sure Bruce will share the sollution to all other devs and your favorite other AOSP ROm will have the cure shortly.

Updated 10/24/2012

This is a detailed description of the 6 million or so things that various people have attempted to do in order to rectify the blinking data connection problem plaguing T Mobile USA users on AOSP ROMs for the Sensation. This issue is non existant in Sense based ROMs.

The problem has something to do with how the Sensation authenticates itself with the T Mobile Data Network. It's not based on the cell towers as voice calling is unaffected. The theory is that the AOSP framework lacks the proper authentication certificates for part of the data network and when the phone is routed to that part of the network, it gets kicked off teh network, then continually retries to connect.

This was and issue on the Sense Gingerbread Stock ROM in 2011 but T Mobile and HTC patched it. All Sense ROMs are free from this bug. But no one knows what exactly the patch was so AOSP ROM's have not been able to be cured yet.

Short version....

Problem started for me on Bruce's CM10 rom. But it's reported on all CM10 variants and most CM9 ROM's as well.

One day I noticed that data wasn't connecting well. It would blink on and off. Sometimes it would stay on, but if I turn it off then right back on, it might go back to blinking.

The problem exists on all AOSP roms (AOKP, CM9, all versions of CM10) even after full wipes and restores of known working nandroids.

Cell signal for voice calls works perfectly. No problems whatsoever. So the phone is connecting to T Mobile. It just won't get data.

Long version....

To fix this I've tried the following...and how each does or doesn't work.

Switch to 2G networks only and switch back. Problem remains, and still blinks E on the EDGE networks rather than being solid on them.

Updated the radio. Problem remains.

Updated the entire firmware package. Problem remains.

Superwipe and flashed Sense, verify data works well. Then regular wipe and flash a fresh install of CM10. Problem remains.

Flashed clean version of CM10 and fixed permissions. Problem remains.

Made calls from the phone. Some people have reported that this helps temporarily.

Sent myself a text message. Some people have reported that this helps temporaliy.

Turn on airplane mode for a minute then go back to normal. Some people have reported that this helps temporarily.

It's not related to Wifi at all because I've created the error on fresh installs of CM10 before ever turning Wifi on.

Formatted SD card. Problem remains (and just to be sure I got the error while the blank formatted SD was removed from the device)

Checked the APN's 100 times. They are correct.

Spent an hour on the phone with T Mobile. Their tech said everything looked good on their end. He cleared the SIM and reactivated it. Problem remained.

Other people have gotten new SIM cards and found that while they helped right away, the problem eventually came back.

The only things that have shown any help to multiple users are in bold above. There are various reports of 100 other 'fixes' that people swear fixed the problem for them. But all of them involved the phone disconnecting from the network and reconnecting. That appears to be the key to get data working again temporarily. Making calls and sending yourself text messages also forces authentication on the T Mobile network without breaking the original connection.

If you want more details or want to review the logs to see if you can figure it out, logcats of the problem are located in this post! Click here for logcatty goodness!