These two version are not identical.

Question 1:

Is there any functional difference between them?

I am asking because I can ramboot "Universal" XP without boot.ini/ntldr/ntdetect.com, by using bootmgr/winload.exe. It works for versions up to and including Vista and makes no difference wether system32\winload.exe or system32\boot\winload.exe is used as osloader. Look here for wimbooting diskless xp; http://sanbarrow.com/phpBB2/viewtopic.php?t=1695 (faster network transfer because of high compression - 550 Mb >> 220 Mb)

Question 2:

Is there a known way of forcing winload.exe to read txtsetup.sif, as in PE.

Question 3:

Is winload.exe even supposed to handle NT5.x PE? You can sure enough set "winpe yes" in BCD, but the only effect is that systemdrive is mapped to X:\, with winload.exe still seeking after config\system without reading txtsetup.sif (and non-volatile hives loaded to ram).

Joakim

For those that do not know;

winload.exe of version up to and including current Vista will automatically detect nt5.x (meaning you don't need ntldr and ntdetect.com). Which means BCD entries for nt6.x also works for nt5.x (not requiring {ntldr} or {legacy}). That is for non-PE though.

Joakim