From what I've understood about the upgrades, Bungie/Gearbox/Microsoft did a patch-fix to disable packets that were unsigned from working. From what I also understood, most of the updates after 1.06 were security fixes, not changes to the actual engine.

In theory, would it not be logical to argue that Yelo/Open Sauce would work on 1.05?

It's Yelo. If he wasn't aware of this "bug" then how did he base his code off of that patch? And a better question, how do you know that is what he did? You contradicted yourself, acting like you know more than you actually do.
I'm going to say that nobody here besides him and maybe a few others knows exactly where he based his code from.

Now, back to another theory.

Back before 1.06, it was possible to send unsigned packets to the server. Usually, this would be used for malicious intent (obviously why the patch was released to stop this.) What if, and this is a big if, we drop back down to 1.05 just to test the theory that this patch is the source of the device synchronization error that has eluded a fix for ages.

Until recently, this hasn't been a major problem obviously, we just stick to biped syncing across things to make things click. This is no problem until we start having a whole bunch of bipeds. The whole reason for this 'test' is to see if we were right. If we are in fact right, then we can proceed from there. If not, we tried something that (to our knowledge) hasn't been tried before.

It sounded to me like you were pretty confident that is why the server can't send modified packets to the clients, why are you second guessing yourself?
We are pretty confident in this. That's the reason we're trying to go through with this, is to see if this patch that Bungie released is what stopped it from even starting back at 1.05. For all we know, Bungies own solution to a hacker exploited problem could be the curse that's stopping this.

I do have to say, the arguments that are against this is...quite staggering. Why would someone be against something that actually wouldn't cause harm and even further progress the Halo CE community?

Wow, I can not believe you just said that. So you want to compare two different versions of the Halo executables, let's say 1.04 and 1.05 as an example, and you think doing a simple hex compare will show you what code was added/removed? Seriously? That won't work because the memory addresses for the same code in the executable will have changed, so the hex will drastically differ.
I will agree with you there. Here's an even simpler example: I take the MD5 hash of 'a', and the MD5 hash of 'b', and compare them. There is absolutely no chance to know which is which unless you know what they are.

I doubt anybody will go through the trouble of downgrading OS to a previous version. You would be better off figuring out how to get the client to accept modified packets, and add that into the current version. Downgrading OS will undoubtedly cause a lot of issues and bugs that you will have trouble tracking down and fixing.
Don't you think we have already figured this out? The whole point of doing this is to see if we are right to begin with! Why bother modifying a packet to the 'signed' version if it won't work to begin with. Wasted effort brings no results. If we figure out that the patch was the issue to begin with, then we can confirm these results and figure out how they changed the packets.

Don't you mean "in the form of an edited version of Open Sauce's source code". Just having a dll file won't help you much if it can't be implemented into another person's OS codebase.
Well duh.

How are you downgrading Yelo Battery without the source code? Unless you were referring to Open Sauce, which in that case, how do you plan on doing this if you cannot even add a script function to the game using Open Sauce?
I'm just curious as to how this even relates to what we're discussing. Care to elaborate?

I shall now sit back, and try to figure out why someone here would, instead of help us, argue against us in something that might actually change the future of how Halo Script needs to be written on devices.