32b upgrade to 64 b; Boot.plist

Hi beautiful ideals!

Decided to install Virtual Machine & Docker in this 14 year old ex-Macbook.

In which I installed Debian "Buster" i386 32 bits. As some of you know, I did some failures during installation, the dvd player "hung" a bit several times, so I saw it installing at least 3 times. I made a puzzling observation: 64 came up a lot of times, but the machine seemed to handle it. ("Is it 64 bits anyway?" I wondered.)

Now I found the following information in Wikipedia:

" Mac OS X 10.6 is the first version of macOS that supports a 64-bit kernel. "

n Snow Leopard, most built-in applications have been rebuilt to use the 64-bit x86-64 architecture (excluding iTunes, Front Row, Grapher and DVD Player applications).^[43] They will run in 32-bit mode on machines with 32-bit processors, and in 64-bit mode on machines with 64-bit processors.

A change to the com.apple.Boot.plist will also enable users with compatible computers to permanently boot into 64-bit for those wishing to do so.

After upgrading the kernel from 32b to 64b, if advisable & possible.

How to do that? Clean reinstall I guess optional, but will that suffice?

Geg