PART1
Increase the number of games in ps3gen. ps3gen after formatting creates only 4 games. You can create up to 255 games (FF in hex)
1. You will need a hex editor. I use Winhex. Run winhex. Open Tools-> Open Disc. Select the hard disk is formatted in ps3gen.
2. Go to Offset 2000B
3. You will see this

4. Change the value of the byte at offset 2000B for the desired number of games and add bytes 05D3A0 and 0B as much as you need. An example. I did 5 games. Do not forget after change winhex click Save.
5. Here's what happened

PART2
Change Partition Size:
1. Go to Offset 1CC
2. Change 1 and 2 bytes. Maximum size of partition 2Tb
You can easily make any partition size to 2TB. For example: You want to make a 500GB partition. Change the byte 1 to 3E and byte 2 to 80.
Enjoy!
From Russia with Love!
xerius