So heres how I installed Windows XP on a Lenovo X1Carbon type 20xx. Using Nlite, I slipstreamed the correct Chipset drivers so that XP could communicate with the SSD. I found the drivers exactly where you said they were! After that I made an install USB with Win to flash. Upon install, when XP asked if I needed to install any third party scsi or raid drivers, i pressed f7 which disables AHCI during install. You will lose functionality but it's the only way to do it. After the first reboot, I received the Hal.dll is missing error. I simply rebooted, chose to boot from the USB, and picked the second boot option, not the Hal debug option which will just result in a controller I/O error. The install completed successfully after that and now I just have to go about finding some drivers which may be difficult.