China DOS Union

My question is:
How can I rewrite the hard disk boot parameters so that when the computer starts it is forced to boot from the rewritten area, load the NIC driver and network protocol from a low level, run a login program I wrote myself to connect to the server, verify identity, then completely release itself, and start the multi-OS boot selection interface, and after choosing the corresponding operating system, boot that operating system.

Thinking about it, it shouldn't be difficult, jump to the boot area

Thinking about it, it shouldn't be difficult. Jumping to the boot area requires rewriting the code in the master boot record, but loading drivers and protocols is much more complicated, because the network devices when the program runs are very complex and not easy to match. I'm afraid this section of code can't fit into the rewritten area.