For some reason whenever I start the machine with the (etcher-made) flash drive inserted. All of the EFI starts to freeze. Even when I start the machine without the usb-drive. The minute I insert it, it starts hanging. Weird, because I was able to install a linux distro in the same way. Any thoughts? Or perphaps try another haiku version? Perhaps r2, and upgrade from there?
Yeah, that efi boot on Mac doesn’t work for a reason unknown to me. I got further by installing refind The rEFInd Boot Manager: Installing and Uninstalling rEFInd and booting an usb stick from there. One more hint: you can hit space right after pressing return to boot haiku to enter the boot menu for further haiku book options.
Thanks. Refind is installed. I get the error (after pressing space): No Sys loader!
No Sys loader! message comes from mbr boot code. Try this from macOS:
brew install gdisk
sudo gdisk /dev/rdisk0
p
to print the partition table.
I’ve tried it with the beta 5 on this machine too. It is booting until the blue clean “desktop” and the “hand” cursor, then this screen shows up:
What does that mean? 
A userspace application called the debugger, and this seems to be part of app_server otherwise it would have gotten the gui debugger.
For this issue, just open a ticket here https://dev.haiku-os.org