# ubuntu-on-imac

## 2011 IMAC

### Disable startup chime

The startup chime volume is controlled by the EFI variable SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82. So it can be muted with

```
printf "\x07\x00\x00\x00\x00" > /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82
```

Bear in mind that the file may have the immutable bit set by default, which will prevent even root from overwriting the file. See File permissions and attributes#File attributes. To remove it, issue the following:

```
chattr -i /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82
```

After that, run the printf command and it should overwrite the file properly. Verify the file's contents and then set the immutable bit again with chattr +i once satisfied. 

### Fix screen brightness adjust

Edit /etc/default/grub and modify the GRUB command line to include the following
```
GRUB_CMDLINE_LINUX_DEFAULT="pcie_aspm=force acpi_backlight=native"
```

Rebuild GRUB menu afterwards
```
update-grub
```

### Install mbp fan controll

```
apt install mbpfan
systemctl enable mbpfan
```