So all 1080i players can only play back at 1080 30p, I read the XA2 and A20 if updated to at least 2.7 have the 24p firmware. Any other players that have this ability? Without it your not getting the true 24p and getting that 3:2 pulldown judder.

According to long time reviewer josh zyber, none of the mediatek mpeg decoders used on hd-dvd players are able to decode 1080p60. They max out at 1080i60. The hqv reon chip in xa2 line doubles it after mpeg decoder to 1080p. 3rd generation units have the same issue. A30 and a35 has abt2015 chips by dvdo and they deinterlace to 1080p.
Later fw somehow allowed the mediated mpeg decoder to output raw 1080p24 which is slightly higher bandwidth then 1080i. If you want 1080p60 its still the hqv or abt chip that does the conversion as this is not possible with the hardware.
It is possible they overclocked the mpeg converter or passed the safe limits for 1080p24 on mpeg converter. A lot of people report overheating and self shutoff.

To answer to your question. A30, a35, xa2 are all true 1080p24 capable after fw 2.7 but most stable is fw4.0. There is still a bug. If you set the player to 1080p24. Mpeg decoder always outputs 1080p24 regardless its dvd or 1080i hddvd. This renders abt and hqv chips useless beside noise reduction. If the material is not film. 24p output results tearing in vvideo.so you have to go in and manually select 1080i or 1080p60 for video material.

Since Blu ray doesn't do 1080p 60, I wouldn't think HD DVD could either just 1080 30p which is just 1080 60i, correct? Just referring to which players can actually decode frame per frame the 24p source without adding in frames. That might explain the shutdown bug on the XA2 then, they must not have got that sorted out before the end. But removing panel fixes.

Blu ray was a little ahead of the game since all players were 24p capable from the start. They sure have drug their feet on making 48p and 60p available, supposed to be here end of year. Not sure though if that's just for 4K or if 1080p will have it too. I hope so, been shooting in 1080 60p and it's glorious.