"New" 1D IV Confusion

My "backup" 1D IV became my wife's camera, and the shutter finally crapped out yesterday.  B&H got us a "new" one today!  After updating the firmware, I deleted all the old settings and set it up just like my old one.  My wife has terrible vision, so she uses Live View, with magnification, often.  I CAN'T GET THE "NEW" ONE TO MAGNIFY LIVE VIEW!  I know Live View magnification doesn't work with Facial Recognition EF; that is NOT on.  As far as I can tell, the 2 bodies are set up exactly the same *except for the Firmware Version*.  I hadn't updated the Firmware in the old body since 1.1.1 came out; the new body has 1.1.5   I can't imagine that a firmware update would kill the capability, but other than that, I'm afraid it may be a hardware problem.  I tried looking for 1.1.1 on line, but I'm getting a message that it's not available for my OS (Win 10).  I could break out the old laptop w/ Win8 and look. . . . I was going to call or chat w/ B&H, but they're closed until Sunday.  Do they offer that type of support?  Anybody here have any ideas?
Thanks in advance.

Even if you could get it to run under Win 10, it probably wouldn't allow you to go backwards. You'd have to send it to Canon but I seriously doubt that they disabled a feature. It has to be some setting that you missed, perhaps in button assignments or some other minor difference.

Here's something that might help:
https://www.imaging-resource.com/PRODS/ ... VEVIEW.HTM

This at least suggests that this function works in manual focus mode - is one camera/lens set to MF while the other is set to AF?

E.J. Peiker wrote:Even if you could get it to run under Win 10, it probably wouldn't allow you to go backwards.  You'd have to send it to Canon but I seriously doubt that they disabled a feature.  It has to be some setting that you missed, perhaps in button assignments or some other minor difference.

Here's something that might help:
https://www.imaging-resource.com/PRODS/ ... VEVIEW.HTM

This at least suggests that this function works in manual focus mode - is one camera/lens set to MF while the other is set to AF?

Got it!  I missed a whole button assignment quagmire when I was setting it up. I’m not sure I’d ever figure it out again w/o copying whatever it was I figured out 6 years ago. Your comment reminded me of struggling w/ that mess back then. Thank you!