As I remember, for 10 or 20 years on x86 execution starts at 32-bit address like 0xffff_0000:0000, not 0xffff:0000 which was used in 8086, am I wrong? Stumbled upon this when tried to disassemble BIOS.

You are correct, I need to edit my post because they both boot up in unreal mode. The 32bit Segment limit is an unreal mode thing.