Protective MBR

[Jethro82]

So as my first pandemic project I created a boot sector game technically it is under 511 bytes, but it's far too large to par down to the 446 bytes or 448 bytes needed to live on a MBR or FAT12 compliant medium.  However it occurred to last week that with a protective MBR I might be able to store it on an MBR in two parts - the first 446 bytes and the 48 bytes for the other 3 partitions.  So my question is this: if a modern operating system(Windows 11 or a modern distro of Linux) sees a protective MBR in the first partition slot does it ignore the data in the next 3?