MENTALNET-INSTALL(1)

Install & Test Guide — Mentalnet GNU/Linux R1 "Ochatime" · Buildroot 2025.02.17 · kernel 6.12.114-mentalnet-intel32 · login root / mnlinux · hostname mentalnet

NAME

mentalnet-install — install Mentalnet GNU/Linux from the live CD to a hard disk. The ISO is a live CD: the entire system runs from the CD with a read-only root filesystem, and the same CD carries the built-in hard disk installer.

SYSTEM REQUIREMENTS

Running the live CD

Installing to a hard disk

• IDE/ATA disk with at least 1 GiB free (the whole disk is wiped)
• The machine must be able to boot from CD (El Torito, BIOS boot)

WHAT'S ON THE MEDIA

The live system mounts its root filesystem read-only from the CD; everything writable lives in RAM (/tmp, /run, /dev/shm and the /var subdirs are tmpfs). Services started at boot:

DNS from DHCP works on the live CD too: /etc/resolv.conf is a symlink into tmpfs that udhcpc writes through.

Default kernel command line

i8042.nomux i8042.noloop noapic acpi=off i8042.dumbkbd=1

To troubleshoot a specific machine, edit the boot entry at the GRUB menu with the e key, change the linux line, and boot with Ctrl-X or F10.

INSTALLATION

Boot & log in

1. Boot the machine from the CD (El Torito boot). Expect the GRUB menu ("Mentalnet GNU/Linux", 10 s timeout) and a kernel boot to a login prompt on the VGA console.
2. Log in as root (password mnlinux).
3. Run: mentalnet-install

Installer prompts

Disk to install to (e.g. sda): sda
Type YES to continue: YES
Proceed with installation? [y/N]: y

• Disk to install to — e.g. sda (the installer lists detected disks with their sizes first)
• Type YES — destroys everything on that disk
• the new partition table is then shown — sanity-check the disk size before continuing
• Proceed? [y/N] — final confirmation before anything is written to the disk

The installer then:

• writes a fresh MBR partition table (root partition starts at sector 2048, leaving room for the GRUB core image)
• creates an ext4 filesystem labelled rootfs
• copies the whole system from the CD
• generates /etc/fstab
• installs GRUB to the MBR and writes the boot menu

When it prints Installation complete!, run poweroff, remove the CD and power on — the machine now boots from its own disk. The installed GRUB menu has a 5 s timeout and boots automatically.

POST-INSTALL

The installed root filesystem is read-write, so all services behave normally: chrony keeps its drift file, dropbear generates SSH host keys on first boot, and logs persist under /var/log. Kernel boot messages are mirrored to COM1 (ttyS0) — handy for debugging headless or semi-broken machines. Login is root / mnlinux, same as the live system. DHCP DNS works the same way (resolv.conf symlink into tmpfs).

Security after install

The default root password is mnlinux — change it after installing (passwd). Then, for day-to-day use, create a regular user and give it sudo privileges (sudo is included in the build):

user@mentalnet:~$ adduser myuser

• add the user to the sudo group, which the shipped sudoers file already trusts: addgroup myuser sudo; or
• enable the classic wheel group with visudo (uncomment the %wheel line) and add the user to it.

Verify that sudo works for the new user before locking root — log in as the user and run, for example, sudo ls /. Once sudo is confirmed working, lock the root account:

user@mentalnet:~$ passwd -l root

TESTING IN QEMU

# live CD, graphical window
qemu-system-i386 -m 128 -cdrom output/images/rootfs.iso9660

# headless (serial console); exit with Ctrl-A x
qemu-system-i386 -m 128 -nographic \
  -kernel output/images/bzImage \
  -append "console=ttyS0 root=/dev/sr0 ro" \
  -cdrom output/images/rootfs.iso9660

# low-memory margin test: same but with -m 64

# NE2000 network test (after login, `ip link` should show eth0 up)
qemu-system-i386 -m 128 -nographic -nic model=ne2k_pci \
  -kernel output/images/bzImage \
  -append "console=ttyS0 root=/dev/sr0 ro" \
  -cdrom output/images/rootfs.iso9660

Full installer end-to-end test:

qemu-img create -f qcow2 /tmp/mn-test.qcow2 512M
qemu-system-i386 -m 128 -nographic \
  -kernel output/images/bzImage \
  -append "console=ttyS0 root=/dev/sr0 ro" \
  -cdrom output/images/rootfs.iso9660 \
  -drive file=/tmp/mn-test.qcow2,format=qcow2,if=ide
# log in, run mentalnet-install, then poweroff and boot only the disk:
qemu-system-i386 -m 128 -nographic \
  -drive file=/tmp/mn-test.qcow2,format=qcow2,if=ide

The serial console should show EXT4-fs (sda1): mounted ... r/w and Run /sbin/init as init process.

BUILDING FROM SOURCE

The repository is not a full Buildroot tree — it is an overlay meant to be applied on top of a pristine Buildroot 2025.02.17 checkout:

wget https://buildroot.org/downloads/buildroot-2025.02.17.tar.gz
tar xf buildroot-2025.02.17.tar.gz
cd buildroot-2025.02.17
# copy from the Mentalnet repo onto the tree:
#   board/mentalnet/              -> board/mentalnet/
#   fs/iso9660/grub.cfg           -> fs/iso9660/grub.cfg (overwrites upstream)
#   linux/linux.hash              -> linux/linux.hash (Linux 6.12.114 source hash)
#   package/php/php.mk,php.hash   -> package/php/ (PHP 8.3.36)
#   .config                       -> .config
make

The committed .config reproduces the released system exactly. The target kernel is pinned to 6.12.114 (source hash comes with the overlay), while the internal toolchain uses Buildroot's 6.12.104 kernel headers — this separation is intentional.

Outputs land in output/images/: rootfs.iso9660 (the bootable live CD / installer ISO), bzImage (the kernel), rootfs.ext2 (a 2 GB raw disk image variant for QEMU testing) and GRUB core images. A full build takes a while; rebuilds after config changes are much faster.

TROUBLESHOOTING

How to tell which build a VM is running: the login prompt prints the build stamp, or check BUILD_ID= in /etc/os-release or cat /proc/version inside the guest.