so deleting that 200mb partition is the fix?
It let me install Windows XP. BUT I discovered that removing the 200 MB EFI partition had side effects. I were no longer able to select a startup disc in the tool in OS X. Neither the OS X partition or the XP partition showed up there anymore. This led to slightly longer boot times, so I was not satisfied with this solution.
This is a step by step list on how I was able to install XP without deleting the 200 MB EFI partition. The key is letting the rEFIt software fix some GUID/MBR issue, halfway through the XP PRO SP3 installation.
1. Install OS X on the entire X25-M as one partition.
2. Use the Boot Camp assistant to create the windows partition. I made the two partitions equally sized at about 37 GB.
3. Start the XP installation. Choose the FAT32 partition created by bootcamp as the XP drive.
4. Continue with XP installation until it restarts.
5. I then get the "missing hal.dll" or "disk error" and cant continue with XP installation.
6. Boot into OS X and install something called rEFIt available from
http://refit.sourceforge.net/ .
7. Reboot and hold the option key down to choose what to boot, and then select "rEFIt".
8. Run the partition analyzer in rEFIt. It will analyze the GUID and MBR tables and will find an "error" and suggest a change.
9. Answer yes when asked if you want rEFIt to do the change.
10. Reboot and restart the XP installation all over again.
11. Remove the FAT32 partition created by bootcamp and create a new NTFS partition instead.
12. Install XP on the newly created NTFS partition.
13. When the XP installation reboots, the "missing hal.dll" error is not shown anymore and the XP installation will be able to continue successfully.
14. Uninstall rEFIt.
15. Start enyoing having both XP in bootcamp and OS X installed on the X25-M.
