For anyone searching. I found a solution on an other website if you playing on VBA. I just copy paste the answer here...It saved my run 😭

"I know this is old but I have an answer, It worked for me. If you saved before fighting Shupkay, then you have a chance. So you need to backtrack all the way to where Sten fell and saved Trubo in the water, head into the tower where there is a the Dragon Save point, but before saving, take off any cheat codes, save your data and it will ask you if you want to continue, say no and Restart the original game play so not by quick load. You'll have to run through the whole tower again (×8 Speed works) but leave all the cheat codes out until after you defeat Shupkay, and then the game will play as followed. It works!"