Hi

I had installed MDT2013U1, recreated SCCM TS with new MDT packages and all steps from old TS.

My new TS has new WinPE boot image, but when I get to selecting which TS to start I do not see new TS.

When I changed to previous winpe boot image than I can see that new TS.

I am trying to deploy Win7x64 Legacy bios.

Before upgrade everything worked fine.

Have you distributed the new boot images to DP's ?.

Can be that my mistake is that I deployed only x64 boot image?

If you are using x64 boot image for OSD, it's perfectly fine. Can you confirm if you have distributed the TS to the DP's. Could you also try creating a TS and link the boot image after you create the TS ? TS Properties  > Advanced > use a Boot image.

TS is on DP, because I can see it on list when I change boot image in TS properties to old MDT boot image.

Do I need to uncheck "Publish to PXE enabled DP" on old MDT boot images?

I can see in logs that PXE boot instructed to boot with new MDT boot image and that my computer is in All Unknown computers group. When I get to list where I choose TS I do not see that TS. And it happens when TS have in properties new MDT boot image, when I change to older one I can select that TS in Task Sequence Wizard window.

TS is on DP, because I can see it on list when I change boot image in TS properties to old MDT boot image.

Do I need to uncheck "Publish to PXE enabled DP" on old MDT boot images?

Yes, but it should also work without that being unchecked.

That is something weird. Your TS should be visible no matter what ever boot image you choose.

Do I need to uncheck "Publish to PXE enabled DP" on old MDT boot images? - As far as you are using the boot images you need not do that.

How PXE boot select which boot image to load if I have two x64? Because one time computer loads with new winpe and one time with old one.

Does old TS which was created with old MDT 2013 will work with new winpe? Because in TS properties I have old winpe but it starts to load new one and next step I got this :

How PXE boot select which boot image to load if I have two x64? 

It's the one with the highest advertisementId. The screen shown above will be shown if the boot images assigned to the TS does not match. 

Yes, boot images did not match. I did not changed them.

To use new MDT I need to recreate them all and change to new boot image.

For temporary solution I removed all deployments where new image was involved.

Old deployments started to work.

I will try tomorrow to deploy again winpe for Windows 10. I have new TS, which today did not worked.

I will restart also my server.