PS3 Removing Petitboot from PS3 SLIM

[infernal_byte]

What is the best way to remove Petitboot from a PS3 Slim (NOR)? I tried to install RR Linux, but I wasn't able to get it to boot and I just didn't have the time to get it working. I came back to my PS3 to play some games, but I noticed that I was having issues loading PS2 games. I learned that there is a flag I can set that helps with the PS2 games, and it did solve my problems. However, I'm wondering if there is a way to completely remove Petitboot from my system? I read that I can use "delete_vflash5.pkg" to remove it from my system, but I have since changed my CFW from 4.84 REBUG (REX?) to Evilnat 4.90 CEX since trying to install RR. I am concerned that running this package could cause a brick. Is there an alternate way, or will this be fine for my system. I preferably would like to return to as "stock" as I possibly can.

 

[Berion]

Connect drive to PC and zeroed 4MiB starting from LBA 473608 (address 0xE741000 in hex editor). OOS areas are not encrypted so it is doable without ERK dumping. But if You will do it incorrectly, PS3 will want format drive. :P If You using Windows, also You cannot agree for disk initialization because this will overwrite PS3PT by MBR or GPT.

But TBH, it is useless to deleting OOS in VFLASH. While You still have OOS area partition after CACHE partition. To get rid of that on fw past 3.16, it is possible only by installing CFW without OOS+ regions presets (which means normal CFWs) and choosing option in recovery menu to Restore PS3 System (which means formatting drive).

If You don't understand "where is what", here is my diagram: