PS3 Can't make NAND backup in FlashWriter because my used console already has CFW?

[zackarhino]

I'm gonna repost my Reddit post here in the hopes of getting more replies:

I'm having a similar issue to another poster where I can't dump NAND because it says my system already has CFW?
This poster has a very similar issue to me:

https://www.reddit.com/r/ps3hacks/comments/1tgtzxk/bought_a_used_ps3_chech2501a_ps3xploit_flash

I bought a holy grail (CECHA) PS3 and I'm trying to put CFW on it. However, I can't dump the NAND from FlashWriter because I get the following error:

You cannot use this tool because you have already installed CFW!

This is after inserting my FAT32 MBR flash drive into the rightmost port and trying to write to USB 0. I'm on 4.93.

Any ideas? I'm a noob. I really want to have a NAND backup before I make any further modifications.

To clarify, I don't think the console has CFW on it, unless I'm mistaken. I can not find anything that would indicate the presence of CFW.

Thanks in advance.

Edit: Sorry, I think I accidentally missed the step about installing HFW. Rookie mistake, sorry about that.