I have a 2011 MacBookPro81 that still works fine but it’s not that speedy so I like to keep a light weight Linux on it. Today I installed Butterbian-XFCE4. It does work well and is fast enough for general internet work.
While the Butterbian ISO 0.3.3 does contain the Broadcom wireless firmware to make the builtin wifi work, it’s not very fast. So my advice is to just use the RJ45 Ethernet port or some open source supported USB WiFi adapter for installation.
Once Debian is installed if you install the packages:
broadcom-sta-dkms and linux-headers-amd64, the much faster wifi driver will be installed and the modules will be compiled and installed. It makes a lot of difference.
Also note that the old Macbooks have some very old 32/64 UEFI firmware that behaves strangely depending on the ISO you try to boot from. The butterbian ISO is fine but if you put it on the latest Ventoy you’ll never get it to work. I had to use a version of Ventoy that was from 8 months ago. The latest Ventoy deleted something not used in the latest hardware but needed on the old stuff.
Butterbian-XFCE4 0.3.3 ISO on its own USB key works as well.