Ubuntu Version
Ubuntu 26.04 LTS
Desktop Environment (if applicable)
GNOME
Problem Description
I recently installed Ubuntu 26.04 GNOME on an Apple iMac14,2 (late-2013 27-inch) and worked through several hardware issues.
I am posting the results as a practical field report for anyone trying to put a similar iMac back into service.
The system is now usable for normal desktop work, web browsing, video playback, music, Google Meet, and general file storage.
Relevant System Information
Hardware
Computer: Apple iMac14,2
Display: 27-inch, 2560×1440
CPU: Intel Core i7, quad-core, 3.5 GHz
RAM: 8 GB
Storage: 1 TB Fusion Drive
GPU: NVIDIA GeForce GTX 775M Mac Edition, 2 GB
Wi-Fi: Broadcom BCM4360
Bluetooth: Apple/Broadcom Bluetooth hardware
Keyboard: Apple Wireless Keyboard
Trackpad: Apple Wireless Trackpad
Ubuntu / GNOME
Ubuntu 26.04 LTS
GNOME Shell: 50.1
Session: Wayland
Xwayland: 24.1.10
The display is running at its native:
2560×1440 @ 59.95 Hz
100% scaling
What I’ve Tried
- Broadcom Wi-Fi
The iMac contains:
Broadcom BCM4360
PCI ID: 14e4:43a0
Apple subsystem: 106b:0111
The wireless interface is:
wlp3s0
The working driver is:
wl
After installing/configuring the Broadcom driver, NetworkManager reports:
wlp3s0 wifi connected
Wi-Fi also automatically reconnects after reboot.
Useful diagnostic commands if troubleshooting a similar machine:
lspci -nnk | grep -A4 -i network
nmcli device status
rfkill list
iw dev
The important point for this particular iMac is that the BCM4360 can be made to work under Ubuntu 26.04, but identifying the exact Broadcom hardware first is important. - Apple Bluetooth
The Bluetooth hardware showed:
Broadcom BCM2046B1 hub
USB ID: 0a5c:4500
Apple Bluetooth Host Controller
USB ID: 05ac:828d
Bluetooth interface:
hci0
The Bluetooth service was enabled:
systemctl is-enabled bluetooth
which returned:
enabled
The Apple Wireless Trackpad initially failed to pair and produced:
org.bluez.Error.AuthenticationFailed
Eventually the pairing process requested a PIN. Entering:
0000
allowed the trackpad to pair successfully.
The resulting device state showed:
Bonded: yes
Paired: yes
Trusted: yes
Blocked: no
WakeAllowed: yes
ServicesResolved: yes
LegacyPairing: no
The important result is that the trackpad continued to work after reboot without having to be paired again. - Apple Wireless Keyboard
The Apple Wireless Keyboard also works.
One confusing problem turned out not to be a Bluetooth problem at all.
A wired keyboard had Num Lock enabled, which caused the Apple keyboard to appear to type incorrect characters.
Turning Num Lock off resolved the apparent keyboard problem.
This was a useful reminder not to assume every strange input-device symptom is a Bluetooth problem. - NVIDIA GTX 775M / nouveau
The iMac has an NVIDIA GeForce GTX 775M Mac Edition.
The system is using:
driver: nouveau
rather than a proprietary NVIDIA driver.
The graphics stack reports:
Wayland
GNOME Shell 50.1
Mesa 26.0.8
glxinfo -B reports:
Direct rendering: Yes
Accelerated: yes
Video memory: 2032 MB
Renderer: NVE4
So hardware acceleration is working.
I therefore did not replace the graphics driver simply because the iMac is using nouveau. - GNOME Desktop Guide / Yelp was pixelated
I did encounter an unusual graphics problem.
Firefox and Files looked sharp, but the Ubuntu Desktop Guide was visibly pixelated/jittery.
The problem turned out to be reproducible specifically with Yelp.
Running:
LIBGL_ALWAYS_SOFTWARE=1 yelp
made the Desktop Guide immediately sharp.
That indicated that the problem was associated with Yelp’s hardware-accelerated rendering under nouveau rather than the display resolution or general GNOME scaling.
Permanent workaround
I created a user-level copy of the Yelp desktop launcher:
mkdir -p ~/.local/share/applications
cp /usr/share/applications/org.gnome.Yelp.desktop ~/.local/share/applications/
Then changed the launcher:
sed -i ‘s|^Exec=yelp %u$|Exec=env LIBGL_ALWAYS_SOFTWARE=1 yelp %u|’ ~/.local/share/applications/org.gnome.Yelp.desktop
I verified that the launcher now contains:
Exec=env LIBGL_ALWAYS_SOFTWARE=1 yelp %u
Then:
update-desktop-database ~/.local/share/applications
After closing and reopening Ubuntu Desktop Guide from the Applications menu, it was sharp.
This workaround leaves the rest of GNOME’s graphics acceleration alone. - Xorg vs. Wayland
I also investigated whether switching from Wayland to Xorg might solve the graphics problem.
The Xorg packages were already installed, including the nouveau Xorg driver.
However, this installation did not provide an Xorg session in the login environment. /usr/share/xsessions/ was absent, while /usr/share/wayland-sessions/ contained the Ubuntu session.
Installing additional GNOME/Xorg packages did not produce a useful Xorg session.
I therefore stopped pursuing an Xorg workaround.
The important lesson for this particular installation was that the graphics problem could be isolated to Yelp without changing the entire desktop session.
Current status
At this point:
• Wi-Fi works
• Wi-Fi reconnects automatically after reboot
• Bluetooth starts automatically
• Apple Wireless Trackpad pairs and survives reboot
• Apple Wireless Keyboard works
• Native 2560×1440 display works
• nouveau provides hardware-accelerated graphics
• Firefox is sharp
• Files is sharp
• Ubuntu Desktop Guide/Yelp is sharp after the software-rendering workaround
One remaining issue I have observed is some pixelation/jitter in the GNOME Settings interface for the Trackpad settings. I have not yet established whether that has the same cause as the Yelp problem, so I am treating it as a separate issue rather than assuming the cause.
Bottom line
This older iMac is quite usable with Ubuntu 26.04 GNOME.
The most useful hardware identifiers for anyone troubleshooting the same machine are:
Apple iMac14,2
Broadcom BCM4360
14e4:43a0
Apple subsystem 106b:0111
Bluetooth:
0a5c:4500
05ac:828d
NVIDIA:
GeForce GTX 775M Mac Edition
nouveau
These are the steps that worked on my particular iMac14,2. They are not intended to imply that every iMac or every Ubuntu installation will require exactly the same configuration.