Greetings!
You actually dont need the toggle_qa.pkg from REBUG. The .pkg file will first check if your PS3 is on 3.41 or 3.55, then it would go ahead and QA Flag your system (You can check if it works when your System beeps and returns to the XMB). PS3HEN´s payload automatically toggles the QA Flag on its own way.
Sources:
https://rebug.me/toggle-qa/
Conclusion to enable the Debug Settings:
Start up your System, update to latest PS3HEN Version, reboot your System, Enable HEN via the XMB Icon, wait a few Seconds, hover over the the Network Settings Icon (Dont click on it), hold L1+L2+L3+DPAD DOWN+R1 at the same time and the Debug Settings + Edy Viewer and Install Package Files will pop up. (If it dosent reboot the System and retry the steps).