You might get better help if you explain a little bit better. From what i gather, you have a jailbroken 4.2.1 iPhone 3G.
You say that the tweaks are not working, after a fresh restore. I am assuming you re-jailbroke after the fresh restore, and installed the said tweaks.
What exactly is not working, (i.e. the phone won't boot, you get a bootloop, airdrop enabler doesn't work)?
You might check, if it is a specific tweak that is not working, that it is compatible with your device The normal repos, will not let you install a non-compatible tweak in most cases. If you use a less than reputable repo, it may allow you to install an incompatible tweak.
Keep in mind also, the device and IOS version are really old, so a lot of newer tweaks may not function with that IOS version.
In of off chance that you did NOT re-jailbreak after your fresh restore, then that would be why your tweaks are not working.