Iso Tool 131 Pspiso Jun 2026

Place the iso_tool folder into the PSP/GAME/ directory of your Memory Stick.

To save space, select “CSO Compression” from the main menu. You will be asked for a compression level (1 = fastest/largest, 9 = slowest/smallest). Level 4 is the sweet spot for speed vs. size.

: It is launched from the Game -> Memory Stick menu on the PSP's XMB. iso tool 131 pspiso

Keep a copy of ISO Tool 131 in your /PSP/GAME/UTILITIES/ folder alongside other essentials like PSPIdent and NandTool. You never know when you’ll encounter a stubborn PSPISO that refuses to boot.

: Copy the unzipped iso_tool folder (which contains the EBOOT.PBP file) directly into your GAME directory. Place the iso_tool folder into the PSP/GAME/ directory

Have you used ISO Tool 131 recently? Share your experiences with PSPISO compression or Prometheus patching in the comments below. For more modding guides, subscribe to our newsletter.

: Extracts .cso files back to standard .iso format. Level 4 is the sweet spot for speed vs

: Users can use the tool to change the appearance of game icons and background images (PIC1.PNG) displayed in the XMB (XrossMediaBar) menu.

Over time, PSPISO files can become fragmented or corrupted due to bad rips. The function in ISO Tool 131 creates a fresh, optimized PSPISO from the original file, fixing header errors.