Yeah forgot about that you will have to edit the version.txt or follow "If you are currently on an older CUSTOM/HACKED firmware..." in rydian guide here .
To edit the version.txt follow this :
1. Press select in xmb and where it says usb device change it from memory stick to flash 0 & connect it to the computer.
2. Search for version.txt without touching anything else.
3. Open it up and change release number from 9.90 to 5.50 or lower than 6.20 or anything you want your version number to be.
4. Change usb device back to memory stick & run the update .
To edit the version.txt follow this :
1. Press select in xmb and where it says usb device change it from memory stick to flash 0 & connect it to the computer.
2. Search for version.txt without touching anything else.
3. Open it up and change release number from 9.90 to 5.50 or lower than 6.20 or anything you want your version number to be.
4. Change usb device back to memory stick & run the update .