Tidusnake666 if you have a 2nd HDD that fit internally in the PS3 (eg. your old PS3 HDD if you upgraded it), then you don't need to wipe all your data.
1- Turn off your PS3.
2- Remove the current internal HDD from your PS3 and replace it with a new HDD.
3- Turn on your PS3, it will start in Recovery Mode and will ask you to format the HDD and plug an USB drive/pen drive with a 3.55 PUP.
4- Go to your PC and copy the OtherOS++ 22GB PUP in the USB/pen drive as /PS3/UPDATE/PS3UPDAT.PUP
5- Plug the USB/pen drive and install the OtherOS++ PUP. Follow the instructions.
6- Once the PS3 finish the installation, it will restart with System Factory settings and it will ask for the date/time and network settings.
7- Follow deank's tutorial carefully (you can continue from step 4).
Once you get your dump_eid0.bin, you can re-install your original 3.55 CFW (eg. kmeaw or Rebug), then shut down your PS3, remove the HDD and put back your original HDD. Turn on your PS3 and all your data (games, videos, music, trophies, save data, users, activations, etc) will be there