Legal Question in Criminal Law in Texas

Depending on what you signed, and when you signed it, there may not be much that you can do. You need to hire an attorney to look into this for you.

The only potential avenue for relief is for you to talk with a lawyer who handles habeas corpus matters to determine if there are constitutional issues (such as ineffective assistance of counsel and / or actual innocence) that could get you back into court.

If your lawyer failed to explain the law as it applied to the facts, then you may have received ineffective assistance. However, if the lawyer explained everything but you made the decision to plead guilty so you could get out and be deployed, that is not the lawyer's fault and is NOT ineffective assistance. And, the plea deal that you go may have been the best that you would be offered - but you had the choice of going to trial and asserting your innocence.

Be aware that while you may not have been the actual shooter, it is possible that you could still be prosecuted as a party to an offense.

It is very difficult to get a case reversed once someone makes the decision to plead guilty. But, if there are issues available, a habeas corpus lawyer will know how to raise them.