[June 4, 2012 - Several sources claim that this hack has been patched.]
The Survival Mode Hack, as we knew it, was patched on May 3, 2012. Since then, a couple of working, alternative hacks have been spreading. One of them uses the Limited Edition Unit Factory (LEF).
The LEF Hack can be done using Charles or Cheat Engine. The hack is very simple to execute using Cheat Engine, and this article will explain this approach. I assume you know how to use Cheat Engine well, and will not go into as much detail as I did in previous articles.
Flagged Accounts
No matter what hack you may attempt, there is an issue you need to keep in mind. As many of you know, Zynga took away Tier 8 units from many players who did not purchase them. Zynga has also been flagging accounts for abuse of Tier 8 units.
The set of players who have been flagged is probably almost the same as the set of players who lost Tier 8 units. Players who were flagged might not be able to use hacks of any kind to produce Tier 8 units (there may be exceptions for technical reasons).
So if you can't seem to make Tier 8 units using this hack or any other hack, either you did something wrong or your account is flagged. In the latter case, be happy with hacking other units (like Super units) or try making Tier 8 units in a virgin account.
Steps to LEF Hack
Step 1 - Preparation
Have a Limited Edition Unit Factory built.
Have all the parts collected for one of the units.
As an example, I will convert a Hind (U113) to a Venom (UB52). Look up the codes for other LEF units here:
Codes: Limited Edition Factory Units
Step 2 - Set Up
Open up the Limited Edition Unit Factory.
Open Cheat Engine and attach the process belonging to the browser your Empires & Allies game is running on.
Step 3 - Convert
Scan for text "U113" including quotes. Replace with text "UB52" including quotes.
Press the button in the game to build the unit. Place it into a depot.
Refresh the game to see your new unit in the depot.