Running Windows XP on a UEFI-exclusive system is an act of digital archaeology. It is unstable, insecure, and prone to breaking. However, successfully hearing that startup chime on a machine that was never meant to run it provides a satisfaction that modern Plug-and-Play operating systems simply cannot replicate.
This is the final trick. You must use a tool like (running from a Windows 10/11 PE environment or another partition) to create a BCD store that can chain-load the XP NTLDR. Alternatively, the rEFInd boot manager installed on a separate small FAT32 partition can detect the MBR partition and "chainload" it, acting as a translator between your UEFI hardware and the legacy XP code.
You must slipstream these into your ISO before writing to USB:
Once you reach the desktop, the real work begins. Modern hardware lacks "official" XP drivers.
Step 5: Post-Installation HurdlesOnce the desktop loads, the work isn't done.
Download the "Fernando’s Modded SATA Drivers" and integrate them via nLite. Without these, the installer will fail to find your hard drive.