What's your Macbook Pro version? Do you still have the OS X partition? If you could not boot back to OS X, you may try to reset it to its factory default. Then you could try to boot from refind (install refind from OS X on to an EFI partition).
You may still need to install Slackware under legacy mode, but don't install other boot manager and manually copy the kernel to the EFI partion and setup bootup script accordingly. Then boot with refind with kernel option "video=efifb".

Hey guys, thanks for both suggestions. Just an update:

* I don't have the OS X partition any more. I tried a recovery but when I had to select which drive to install OS X to, there weren't any drives to choose! Whatever I did to get Ubuntu on this machine, it's removed the ability for the Mac recovery software to detect the drive.

* I've found a live version of Slackware (Liveslak, under the theory that it's a video problem, maybe getting a live version running will allow the install to complete). So the live version runs, but when I try to install it runs out of disk space. The filesystem partition is like ~450 G, so something strange is happening with the install script. Maybe it's trying to install to the /boot/efi partition...?

So, next I'm going to get Ubuntu back on there and try to install reFIND to the EFI partition from Linux. I'll report back.

If you are trying to reinstall OS X you might need to reformat the drives using the OS X install media's disk utilities. As far as using the Slackware live to install, I have no exp. I still think you would have an easier time if you used refind or refit to boot the standard Slackware install media.

For whatever it is worth, when I try to boot elilo directly on my macbook pro with stock Slackware install media I have video issues, but booting the Slackware install media with reind fixes those issues. I think elilo could be tweaked to work right but I just have an easier time using refind.

First off, just some clarification, it is called Slackware Live. liveslak is the collection of scripts used to generate the ISOs, but is not the actual "distro" (if you want to call it that). I've seen Eric correct that on the forum before, so I just wanted to give you the heads up.

And if you install Slackware from within Slackware Live, you'll pretty much end up with a regular Slackware install, so you shouldn't see any difference from using a regular Slackware install disc.

As to the actual problem you're having, while Eric will sometimes respond on the forum to support his projects, he prefers bug reports to be reported on his blog (probably because Slackware Live isn't an official Slackware project... at least, not yet). So if you continue to run into issues with the installation script, I would post a comment on his blog to see if he can help you out.

Good luck

2 members found this post helpful.

Thank you!

Yes, but the issue is the installation process - it blackscreens at the start of it. At least when using the Slackware Live installation, the windows manager is already running so my hope is that whatever setting that made that happen will get copied to the installation.

Alright - I have a solution.

Short answer: I believe the problem would have been fixed long ago by installing using the full "terse" install. When the system was apparently hanging, it was actually installing, but incompletely. Using the 1 line per package install allowed the prompts at the end to be entered correctly and the system installed correctly.

Longer: To make it actually work I figured out how to recovery the Mac install (disk recovery), and then used rEFInd. Additionally, after a dual OS X / Ubuntu boot, I had to remake the hybrid MBR to ensure Slackware could see the partition (just using the GPT table was not enough). I added the Mac partition, the Ubuntu partition, and the Slack partition to the hybrid MBR, and made them all bootable.

However, the short answer might have been fine all along - I'm not sure the extra work in the long answer would have been required if I hadn't been screwing with the partition table in the first place when I removed OS X.

Thanks for everyone's help - all your explorations lead me to the right answer!

1 members found this post helpful.

I cannot think of one "valid" reason why using the "full terse" option would solve "the issue".

Edit: I just wanted to make a note here so that its known I posted this comment as a "red flag", to indicate that there might be other "issues" at play here.

All that is fine, if you think appropriate - I'm just saying "the issue" was that "when trying to install Slackware on a Mac, I got a weird blackscreen with flickering edges".

Then, I did a bunch of random things with partitions, OS X installs, and MBR recoveries.

I tried to install Slackware again, and again got a weird blackscreen with flickering edges.

Then, I rebooted, but noticed that *something* got installed as "Slackware" on that partition. It wouldn't boot, but it was something.

So, I reinstalled with line-by-line package list (i.e. "terse" install), and it worked fine, now I have a running install of Slackware.

I can't confirm anything because I didn't install on the same system I started with, but the issue was identical ("weird blackscreen with flashing edges during install") and the problem was immediately solved after switching to a terse install.

I'm going to guess there might be some kind of disk issue going on, but its just a wild guess.

But switching to "terse" is not intended as a fix for anything, as far as I know.

I confirm that the short answer is the good one.
I'd exactly the same trouble installing Slackware on my MacBook Pro today, until I found your post and tried the "full terse" installation, which worked.
I suppose it's the different way used to show informations which explain it.
Anyway, a big "thank you !" for your report.

Regards,
Sébastien

Apologies for the thread hijack, but can anyone tell me how one gets the (U?)EFI install media for Macbook install in the first place? I don't have a USB CD-ROM, tried unetbootin, it gave me a bootable Slackware USB stick that I tested on another PC where it worked fine, but no joy on the Macbook, just a blank screen after I'd selected the USB stick for boot. I think I have MB Pro 2015 model.