STILL cannot boot a non-UEFI CD on my UEFI Win 7 64-bit - any fix ??

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A year later, and I discover again that I STILL cannot boot from a non-UEFI CD on my UEFI Win 7 Pro SP1 64-bit Dell Optiplex 7010 MT even though "Enable Legacy ROMs" is ENABLED in the BIOS and Secure Boot is OFF.

My original details are here - Cannot boot from CD-DVD in LEGACY mode - NOT Secure Boot NOT UEFI - General Hardware - Desktop - Dell Community

That thread from a year ago describes the issue but then goes off on a tangent into my (successful) experience in establishing dual-booting, but THIS ISSUE remains. My Dell Optiplex 7010 MT (which is now dual-booting Win 7 Pro SP1 64-bit and Win 10 Pro 64-bit) will NOT BOOT a legacy CD that is not UEFI even though "Enable Legacy ROMs" is CHECKED in the BIOS and Secure Boot is OFF. (My BIOS is A20.)

What is the fix??

Please reply here, not in my old Dell thread above. Thanks.
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Update - I have now made TWO bootable CDs of Macrium Reflect. These two CDs show the problem.

First, in my old Dell Optiplex 755 Win XP Pro SP3 32-bit machine, I installed Macrium Reflect Free and made a bootable CD with the included Win PE. I assume it will boot in my XP machine. However, that CD will NOT boot in my other PC, which is my Dell Optiplex 7010 MT that dual-boots Win 7 Pro SP1 64-bit and Win 10 Pro 64-bit, even though the BIOS in this Dell Optiplex 7010 MT ENABLES Legacy ROMs.

Second, in that other PC (my Dell Optiplex 7010 MT that dual-boots Win 7 Pro SP1 64-bit and Win 10 Pro 64-bit), I again installed Macrium Reflect Free (with 64-bit architecture) and made a new bootable CD (with the lowest level of Win PE, which is 3.1), and that CD WILL boot in that second machine.

Why are we being tortured this way? I have other bootable CDs from my XP days - is there any way to get them to boot in the second (Win 7 Pro 64-bit) PC?

Thanks.
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AddRAM - You mean when I turn the 7+10 PC on? It actually boots in UEFI. And I have the AHCI drivers enabled for the boot into Win 7. (See https://support.microsoft.com/en-us/kb/922976 .)

That wild man Speedstep has been trying to teach me something about UEFI at STILL cannot boot from legacy CD on UEFI Win 7 PC - DELL WHY NOT? - General Hardware - Desktop - Dell Community , but in my case Secure Boot is OFF. I thought that Enable Legacy Option ROMs being ON in my BIOS settings should fix this issue, but apparently not.

Thoughts?