I have an additional information about that method:
You have to find the Value for your stage via GameGuardian as shown in the quote: --> encrypted Dword
To reach a high level stage without getting "Teapot" just do it in multiple steps:
Edit the Stage Value you found (by using the above shown steps 1-5)
edit the Last 4 numbers and press ok. after each change, to have an effect to the game.
You are safe if you do a stageskip not bigger than 650 per single skip.
Here's what I do Works with latest update form 20th October):
1. find the stage value (encrypted Dword) should look like -1.908.68x.x x x (only change the last 4 numbers)
2. change the last the numbers to 3.209 ---> Stage 650
3. Press "Yes"
4. Without retunrning to the game, just edit the number again, this time to 4.682-->> Stage 1224
5. Press "Yes"
6. Change the number again to 3.902 and click yes --> 1852
7. repeat with numbers 5.406 (stage 2332), 4.821 (stage 2900), 6.554 (stage 3486)
8. On the last stage I just wait for a ferry to get gold and lvl all my heroes to kill that Boss in the level, so the stagenumber in the Game will update.
Now you can use Prestige and start all over again, GameGuardian has still the stagevalue an you can edit it again and so on, and so on.
I think if you close the game and restart it, the Stagenumber should update aswell, but you have to find the Stagevalue in Gameguardian again.
Stagevalue (Dword encryptet) -1.908.68x.x x x
3.209 for Stage 650 4.682 for Stage 1224 3.902 for Stage 1852 5.406 for Stage 2332 4.821 for Stage 2900 6.554 for Stage 3480
You don't have to go back ingame for the change to apply, just don't forget to click on the "yes" after each edit, otherwise you'll get the teapot message.
The Number on top of the game (actual stage) won't update
until you restart the game,
or kill the current stage boss (which I prefer to keep GameGuardian results saved, an edit them again right after you use Prestige)
Stagenumber has to be updated to be able to do Prestige.
Stage 3480 is my personel max, if anyone else got the needed values for stage 3500,4000,4500,.... please add them here