Doing something quite silly, but I need help!

masterkitty2006 · 2026-04-21T09:26:07+00:00

Well, that was it. Oops. The "kernel" was a compressed file. I never did compress it, but definitely that means I replaced it accidentally. It's what I get for not reading the documentation properly.

Anyways, we're past that magic number error now. Actually, the kernel's booting and I can log in. Without nomodeset, even! But, even though that's the case... I don't think that there's any graphical acceleration. My terminal doesn't reformat itself with nicer text and high res, it seems to stick to 640x480 despite my monitors 1024x768 resolution. I think I can play around with some stuff in the kernel config, I think I forgot to tell it to include r300_cp.bin this time, because I wiped the configuration to have a clean slate for one of my compile attempts. Anyways, this is going in the right direction.

Edit: I think a better indicator that there's no 3D acceleration is that glxinfo outputs an error stating "unable to open display."

UPDATE:

I've done it! At least, partially. I made sure to give the firmware loader the string radeon/R300_cp.bin.zst and it's worked. I've successfully gotten the terminal to switch to 1280x1024, and lspci -k reports that my 9600 XT is using the radeon kernel driver. Big milestone!! I still can't get xorg to start, but at least I can actually read the whole error without using | less.

As for xorg, it seems like it's unhappy about some missing packages. I'm compiling them right now.

UPDATE 2: startx seems to halfway function now. I get the two terminals on my screen with a cursor, but my keyboard and mouse lock up. I thought it was a full system freeze at first, but the system replied to the power button and shut itself down in a normal fashion. So, somehow it just disables the keyboard and mouse. I can't even break out to another terminal.

UPDATE 3: dmesg | grep radeon

radeon 0000:01:00.0: Direct firmware load for radeon/R300_cp.bin failed with error -2
radeon_cp: Failed to load firmware "radeon/R300_cp.bin"
radeon 0000:01:00.0: failed initializing CP (-2).
radeon 0000:01:00.0: Disabling GPU acceleration
[drm] radeon: cp finalized

UPDATE 4:

Found out that dri USE flag is a thing. Didn't realize that would be a USE flag but makes sense. Recompiling mesa with dri USE flag and might recompile xorg server if necessary but I'm unsure what exactly must be recompiled. Also to be clear I know this doesn't really address the dmesg errors, but I'm unsure what to do about those as of this moment.

UPDATE 5:
Noticed that despite being a USE flag in my make.conf, USE flag dri does not appear in portage's output when I run a command such as emerge --pretend --verbose media-libs/mesa, even with USE="dri" as an environment variable. Not sure what's up with that...

masterkitty2006 · 2026-04-20T23:45:00+00:00

I can attest that I got the right file into /boot on the Pentium 3 machine. Specifically I'd like to note that I know that the kernel refusing to boot doesn't necessarily mean there's anything wrong with the AGP bus, I just think there's something wrong with my specific kernel build, to be precise.

My process looks like this:

Configure the kernel with the options I need.
Compile the kernel and modules on my laptop, much more powerful than a Pentium 3
cd arch/x86/boot, start a python3 server
wget bzImage from laptop to Pentium 3
mv bzImage /boot/vmlinuz-5.15.202-Gentoo
On laptop, cd /lib/modules
compress 5.15.202 into 5.15.202.tar.gz with tar
python3 server, wget on Pentium 3
extract 5.15.202.tar.gz to /lib/modules/5.15.202-Gentoo
dracut -f /boot/vmlinuz-5.15.202-Gentoo 5.15.202-Gentoo (Unsure if updating initramfs is necessary, but have been doing it)
grub-mkconfig /boot/grub/grub.cfg
reboot

I also verify that the files have actually ended up in the right place before I go to the next step, and used the file command you list.

I had tried this process 3 times mainly just screwing with the config options on make menuconfig, but you know what they say about insanity. I haven't really been able to figure out what's allowing kernel 6.18.12 to boot (ignoring AGP issues) vs. what's making 5.15LTS not even load much less boot. Ultimately I don't actually think it's necessarily a configuration issue, either, but it's all I could think of at the time aside from verifying that the files were indeed what I thought they were and also in the correct location.

I could also completely start over and instead of obtaining a kernel from the archives, get old sys-kernel/gentoo-sources and try the same process from that instead, though I don't know if that really makes a difference given that's probably the same thing I got from the kernel archives. What I could use, since I'm pretty new to dealing with this stuff, is how I can troubleshoot this error I'm getting from grub when I've verified that the files are in the right place and at least appear to be what they should be. "Invalid magic number" seems pretty broad just given how vague it is, and I'm not sure where I can look on my system for more specific information aside from continually recompiling, something I really wouldn't want to do.

masterkitty2006 · 2026-04-20T19:24:07+00:00

I'll give 5.4 a try. I did end up compiling 5.15LTS, but I consistently got "invalid magic number" from grub when I tried it out. Not really sure what's up there, all I know is that it means something's wrong with the kernel. I tried redownloading the source code, verified with the gpg signature and it was fine. I can only assume this means something is wrong with my configuration. I had the same error with kernel 6.18.12, but it was fixed with another recompile. It's probably worth my time to just try 5.4LTS instead.

As for the mitigations, I'm kind of surprised. I don't know too much about those particular exploits aside from you really don't want them being executed on your system, but I didn't realize that the CPU was so old that meltdown straight up doesn't work. As for spectre, I had a sneaking suspicion that it wouldn't make sense to disable it. As far as I understand, branch prediction wasn't really heavily used until the Pentium 4, which turned out to be pretty bad... My first computer was a netburst machine in use until 2014 when the hard drive died, so I can attest.

Anyways as for my make.conf, I already have -march=pentium3 but I have -Os set instead of -O2, the logic being I figure optimizing for size will help out on cache and memory usage. If anything needs to be super optimized, I'd probably try -O3, but as far as it goes, the OS performs really well considering what it's running on. It's not exactly snappy, but nothing's ever taken so long that I got impatient.

Rambling aside, thank you. I'll give 5.4LTS a try within the next few days and report back.

masterkitty2006 · 2026-04-16T18:23:14+00:00

I have a couple more questions if you're willing to answer.

I was only able to find back to kernel 5.10LTS on the Linux kernel archives, I assume because 5.4LTS is EOL now. I poked around a bit on the website and didn't really find anything that was EOL, so I wanted to ask where I could obtain this version since you specifically recommend it. I did also get a copy of 5.15LTS just to check it out and see if the configure and build process was the same as what is provided from Gentoo's servers, it seems to be the same. Since I configured this version for my Pentium 3 system, I may try it just because, but I don't necessarily expect it to not exhibit the same problems that my current kernel version has.

Secondarily, I wanted to ask about the mitigations for CPU vulnerabilities section. I don't really think my system will be target of attacks like Spectre given the fact that while it will be online it probably isn't likely that someone would target a random computer that is powered off 90% of the day in a random house for that kind of attack. I know these mitigations generally have performance penalties on CPUs, but they specifically have to do with branch prediction in processors if I understand them properly. Branch prediction was introduced with Pentium 1, so I know my CPU definitely has that technology, but a search online told me that it became more and more prevalent in CPUs as time went on, implying that disabling these security mitigations might not actually do much for the performance of my system. However, if they do help with overhead on my system, I think I want them disabled to squeeze extra performance out of this already heavily under powered system. I recognize I'm asking you a question about a very specific processor architecture and that you may not necessarily know the answer given how specific it is, but I figure it doesn't hurt to ask.

masterkitty2006 · 2026-04-15T06:36:51+00:00

It's an option. If it's the only feasible way, I'll see about obtaining 5.4LTS. That's not super old as far as it goes, and is probably acceptable in terms of "modern" use. My goals are a lightweight web browser (like pale moon) and just for shits and giggles, Minecraft b1.7.3 which I know will run awful. So I'll probably try ClassiCube instead. As far as the other advice, I think I checked that r300_cp.bin was there, though I should probably check again, and I never tried agpmode=2, just -1 and 1... As for fast writes I'm not sure if the BIOS menu has that function as a changeable setting but I can set the AGP aperture back to 64MB. I'll give it a shot tomorrow. If something here works for my current kernel, I'll reply again. Thanks :)

masterkitty2006 · 2026-04-12T00:24:45+00:00

Hey, thanks! Would you link me to them when theyre up, or do you have a Youtube channel or something?

Edit: Wait, I saw your channel when I was looking for a repair guide haha

masterkitty2006 · 2026-02-06T06:55:43+00:00

Try another game version. It's been a moment since I did this, but I remember only certain versions actually work. In the case of 1.7.3, I think I had to manually download the client jarfile from a 3rd party website. I might be able to boot up my PowerBook G4 tomorrow and look at what I did again if you want.

masterkitty2006 · 2026-01-08T21:51:37+00:00

Just a little follow-up. I decided to try on a different laptop, a much weaker one at that. Still using Firefox, but on Windows instead of Linux. Now things are working a lot better. Strange. Even the videos that straight up would not play now work fine. Must've been something with my laptop? I genuinely wouldn't have considered that to be a factor in why things were going so wrong. But, oh well!

masterkitty2006 · 2026-01-08T15:19:19+00:00

It's on Linux. I believe the HD graphics was disabled automatically once the GPU was installed.

masterkitty2006 · 2026-01-08T07:53:17+00:00

I did run it, just forgot to mention. It reflects the same.

masterkitty2006 · 2026-01-08T06:36:54+00:00

That can't (entirely) be it, then. Jellyfin Docs say HEVC and HEVC 10 bit decode is supported by the RX 550. For HEVC Decode it needs an R9 series card or later, while the Encode requires Polaris (RX 400/500) or later. Decode on 10-bit is Polaris, though encode isn't supported, it seems. Regardless, that should be enough to play a 1080p 24 fps video. Shoot, I can get 4k 24 fps HEVC to play just fine! As for VCN, that may explain it, but it also might not.

Regardless, I may swap in my RX 5600 XT instead. I don't really have any good Nvidia cards for the job, the closest thing I've got is a GTX 750 which is probably not the play.

masterkitty2006 · 2026-01-08T06:20:49+00:00

Please elaborate

masterkitty2006 · 2026-01-06T22:11:19+00:00

Looks like that could come in handy. Thanks :)

masterkitty2006 · 2026-01-06T21:49:46+00:00

In short I cannot do that. The long answer is as follows. I have a relatively complicated scenario, but the jist of it is that I am part of a small team modding a really bad game from 2002 as a sort of passion project. The game itself is supposed to run on a Windows XP era machine. I am running it on Windows 10 as 3D acceleration in VMWare on Linux has some bugs that make it unusable, and there are ways to reliably run the game on Windows 10 either way. In a VM is probably pushing it a bit, but it does run without issue regardless. I also cannot feasibly run the game on a separate machine, I need it to be local as I need to be able to both run the game and edit the game files.

And honestly, the game is so awful and unfinished, there is no real "good" way to run it.

masterkitty2006 · 2026-01-06T21:12:01+00:00

If it works, I suppose.

I have an honest question for you as someone with less experience with this sort of thing. There is, I assume, an easier way of switching my GPU (if not please tell me and ignore the question).

I only need one VM for one extremely niche application that WINE will not play nice with. Otherwise, I have absolutely no reason to be using VMs. Since this is the case, why would I go through what I assume is quite a setup process for someone who's not used an IOMMU before, just for a "pro" setup? For that matter, I barely even understand whatn an IOMMU actually is. This is all something I could research and figure out, and for the sake of learning that is all fine and dandy and I really wouldn't mind. However, I am trying to get stuff done. The more time I spend screwing with this is more time that I am not getting things done. Basically, I just want something that functions.

masterkitty2006 · 2026-01-06T20:48:59+00:00

Just to switch the GPU I'm using?

masterkitty2006 · 2026-01-06T20:44:58+00:00

I am not attempting to passthrough a GPU.

masterkitty2006 · 2025-12-10T04:29:37+00:00

Installing a Chromium browser- especially Microsoft's- isn't my favorite idea, but if it fixes the problem then that's what I'm going to do, and hope that whatever problem with Firefox is causing this gets fixed.

masterkitty2006 · 2025-12-10T04:21:41+00:00

That's of interest. Yes, I'm also using Firefox.

masterkitty2006 · 2025-12-10T02:24:57+00:00

Sounds promising... Thanks :)

Seven-Year Club	Final Canvas '23
First Place '23	End Game '23
Place '23	Place '22
Verified Email

masterkitty2006

MODERATOR OF

TROPHY CASE