PS2 Help needed in restoring a PS2 from a 'dirty' setup

[nphuracm]

Here is the thing.
My PS2 is SCPH-90006 (HK). I have installed MechaPwn (DEX, 3.0-rc4) on this unit due to issues running restored game backups, but that was before I discovered that this unit has been modchipped all along (Super-7 E17) and I have had no knowledge of it or its presence. Unfortunately, due to MechaPwn breaking DVD Player and a lack of a proper FMCB setup, I am currently unable to access homebrew by conventional means.
I have prepared a LaunchELF v4.43x_isr disc and it can boot normally. However, though, it is unable to read my USB drives (mass:/ always empty, even when USB drive is confirmed to use FAT12 FS and MBR partitioning; probably due to lack of USB IRXes?). There are also a lot of issues when using a separate DVD+RW to store the intended ELF files, like MechaPwn freezing on "Backing up NVRAM..." or FreeMCBoot installer returning to Browser even with all required files present on the USB.
My primary goal was to restore DVD functionality, probably region-unlock it even, but first I need to get myself a clean, conventional homebrew environment to keep things from being confusing.
What can/should I do in this predicament?

 

[Berion]

FAT12? It was never recommend to use. In theory FAT12/16/32 should be supported but better try with FAT32. I don't know what specifically uLE ISR You using, maybe exFAT oriented not reads anything else than that fs, I dunno.

DVD+RW shouldn't be used in the first place. Not only it is Plus which PS2 ODDs not likes but also RW which is stressful for them.

USB modules are build-in in all uLE's. You can use external if You wish (defined in LAUNCHELF.CNF).

To restore, You need again run installer and restore NVM backup and have hope modchip will not mess with that process. Without it, probably You are screwed.

 

[nphuracm]

I have attempted formatting the USB as either FAT32 or exFAT but my wLE failed to pick either of them up.
If relevant, here is my wLE's version information:

wLaunchELF v4.43x_isr Wed Nov 2 13:19:09 2022
commit: cbc663b [based on commit 41e4ebe]
Build features: SMB:0 ETH:1 IOP_RESET=1​

I have only DVD+RWs available on hand, and I don't feel like wasting more DVD+Rs. Sorry.
I must also note that the DVD+RW in question is not used to boot wLE, but rather used to store auxiliary data like the MechaPwn Installer, FMCB Installer and DVD players.

What is the default filename of MechaPwn's NVRAM backup again? If I ever fail to locate it, is re-running MechaPwn and setting a consumer signature that matches my system feasible?