Every DoRoyal VPS supports custom ISOs. If the operating system you want is not in our template list, you can boot your server from any compatible installer ISO and install it yourself. This article explains how it works, the requirements your ISO must meet, and how to troubleshoot common errors.

How Custom ISOs Work

Instead of uploading a file, you provide a direct download URL to the ISO. The King Panel streams the ISO from that URL and attaches it to your VPS as a virtual CD/DVD drive. Nothing is permanently stored on our side; the image is read over the network while it is mounted.

Requirements: Read This First

1. The ISO must be ARM64 (aarch64). DoRoyal VPS plans run on ARM (Ampere Altra) hardware. x86_64 (Intel/AMD) ISOs will not boot on your VPS, even if they mount successfully. Look for downloads labeled arm64 or aarch64. See our article ARM VPS Explained: Advantages and Limitations for background.
2. The URL must be a direct link that returns HTTP 200. Redirects are rejected for security reasons. This is the most common cause of the "supplied URL is invalid" error (see Troubleshooting below).
3. The URL must use http or https and be reachable from the public internet. Links that require login, cookies, or tokens that expire will fail.
4. The ISO should support UEFI boot. ARM virtual machines boot via UEFI. Mainstream distribution ISOs (Debian, Ubuntu, AlmaLinux, Rocky, Fedora, FreeBSD) all support this out of the box.

Step by Step: Booting From a Custom ISO

1. Log in to the King Panel and open your server.
2. Go to the Media section.
3. Click Custom CD/DVD. (If a standard ISO is currently mounted, unmount it first; the button is hidden while other media is attached.)
4. Paste the direct URL to your ARM64 ISO and confirm. The panel validates the URL and mounts the image.
5. Set the boot order so the CD/DVD drive is first, or simply reboot; most installers take over automatically when the disk is empty.
6. Open the Console (VNC) and reboot the server. You will see the installer boot, exactly as if you had inserted a disc into a physical machine.
7. Complete the installation to the server's main disk. Install the OS to the virtual disk shown by the installer (usually /dev/vda).
8. When the installer finishes, unmount the ISO in the Media section and reboot. Your VPS now boots from its disk into your freshly installed OS.

Before You Reach for a Custom ISO

Debian, Ubuntu, AlmaLinux, Rocky Linux, Fedora, CentOS Stream, and Oracle Linux are already available as one-click templates in the King Panel. For those, a template reinstall is faster and integrates with the Client Area (root password display, provisioning). Custom ISOs are for everything else.

Example ISO URLs That Work

These operating systems are not in our template list, ship official ARM64 installers, and the links below are direct and redirect-free (verified at the time of writing). Always check the vendor's site for the current version and update the filename accordingly:

• Alpine Linux (tiny, security-oriented; the virt build is made for VMs):
  https://dl-cdn.alpinelinux.org/alpine/latest-stable/releases/aarch64/ (pick the latest alpine-virt-*-aarch64.iso)
• FreeBSD:
  https://download.freebsd.org/releases/arm64/aarch64/ISO-IMAGES/ (choose a release, then the disc1 ISO)
• OpenBSD:
  https://cdn.openbsd.org/pub/OpenBSD/ (choose a release, then arm64/installXX.iso, e.g. 7.9/arm64/install79.iso)
• Kali Linux (penetration testing; note our acceptable use policy applies):
  https://kali.download/base-images/current/ (pick the installer-arm64 ISO; use kali.download, not cdimage.kali.org, which redirects on file downloads)
• openSUSE Tumbleweed:
  https://ftp.gwdg.de/pub/opensuse/ports/aarch64/tumbleweed/iso/openSUSE-Tumbleweed-DVD-aarch64-Current.iso (the official download.opensuse.org URL is a mirror redirector; use a specific mirror like this one)
• Void Linux:
  https://repo-default.voidlinux.org/live/current/ (pick a void-live-aarch64-*.iso)
• Gentoo (minimal install CD):
  https://distfiles.gentoo.org/releases/arm64/autobuilds/current-install-arm64-minimal/ (pick the .iso)
• NixOS:
  https://releases.nixos.org/ (browse to your release under nixos/ and copy the final nixos-minimal-*-aarch64-linux.iso URL; the channels.nixos.org convenience links redirect and will be rejected)

Not available on ARM: Windows (no licensable ARM server images), pfSense/OPNsense, TrueNAS, and most appliance-style NAS or router distributions currently publish x86_64 images only. These cannot be installed on your VPS regardless of URL.

Troubleshooting

"The supplied URL is invalid. A URL must be formatted correctly and return a 200 HTTP code. Re-directs are forbidden."

The URL you entered does not return the file directly. Common causes:

• GitHub release links. URLs like github.com/vendor/project/releases/download/... always redirect to a storage backend, so they are always rejected. Download the ISO yourself and re-host it somewhere that serves it directly (your own web server, object storage with a public direct link), then use that URL.
• Download pages instead of files. The URL must point at the .iso file itself, not at a page with a download button.
• Mirror redirectors. Some projects publish a "closest mirror" link that redirects. Browse the mirror directory directly and copy the final file URL instead.

Tip: You can test a URL from any Linux or macOS terminal: curl -sI YOUR_URL | head -1. You want to see 200, not 301 or 302.

The ISO mounts but never boots, or shows no bootable device

• The ISO is almost certainly x86_64 instead of ARM64. Double-check the filename and the vendor's download page. An x86 ISO cannot boot on an ARM VPS under any circumstances.
• Some niche projects simply do not publish ARM64 images. In that case the OS cannot be installed on your VPS. Often there is an ARM-friendly alternative that achieves the same goal; see below.

The installer boots but is extremely slow

The ISO is streamed over the network from the URL you provided. A slow source server means slow reads. Prefer official distribution mirrors or re-host the ISO somewhere fast.

The OS I want has no ARM64 ISO

Check whether the underlying software runs on ARM even if the appliance ISO does not. A common example: NAS or home-server style distributions that are essentially a dashboard on top of Docker. Their dashboards often install fine on a standard ARM64 Debian or Ubuntu base, since Docker and most containers are multi-arch. See Installing Software on an ARM VPS for details.

Important Notes

• Custom OS installs are unmanaged territory. We guarantee the virtual hardware boots your ISO; the installation and everything inside the OS is your responsibility. See What Does Unmanaged VPS Support Cover?
• Reinstalling from our templates remains available. If a custom install goes wrong, you can always reinstall a standard OS from the King Panel. Warning: reinstalls and OS installations erase all data on the disk.
• The panel root password feature may not work on custom OS installs. Password display and reset in the Client Area rely on our provisioning integration. On a self-installed OS, manage credentials yourself and store them safely.
• You are responsible for what you boot. Only use ISOs from sources you trust, and ensure your use complies with our terms of service.

Need Help?

If a valid, direct, ARM64 ISO URL is rejected or the virtual CD/DVD does not appear at boot, open a support ticket with the exact URL and a screenshot of the error, and we will take a look at the platform side.