ZimaOS officially targets x86-64 computers that can boot in UEFI mode. This November 2025 forum post shared an experimental workaround for older BIOS-only PCs: use Clover as a compatibility bootloader that provides an EFI-style environment, then launch the normal ZimaOS installer through Clover.
The post credits Albert Gutiérrez Muñoz for the original external tutorial and invites community testing. It should not be rewritten as a standard supported installation path because a later user reported a critical failure: the installer completed, but the computer still could not boot the installed ZimaOS after reboot.
Current ZimaOS Still Requires UEFI for the Normal Installation Path
IceWhale's current installation instructions say the BIOS must have UEFI boot mode enabled and Secure Boot disabled.
Use the current supported ZimaOS installation workflow whenever the hardware offers UEFI.
What Clover Is Doing
A legacy BIOS does not natively provide the UEFI environment ZimaOS expects. Clover is placed on a separate bootable USB and acts as an intermediary: BIOS boots Clover, Clover discovers EFI-capable targets, and the user launches the ZimaOS installer from there.
This is a compatibility bridge, not a conversion of the motherboard firmware.
The Shared Tutorial Uses Two USB Drives
- one USB prepared for Clover;
- one USB flashed with the ZimaOS installer;
- Balena Etcher for writing the ZimaOS image;
- BDUtility.exe and a custom
config.plistfor Clover; - a BIOS-only x86 PC that can boot from USB.
Because the detailed Clover files live outside IceWhale's forum post, users should review the original Clover installation procedure shared in the community post rather than relying on a shortened reconstruction.
Prepare the ZimaOS Installer USB Normally
The ZimaOS installer itself is still the standard image written to a USB device. The experimental part is how the BIOS-only PC gets an EFI boot path to that installer.
The Shared Boot Sequence
- configure the old PC BIOS to boot from the Clover USB;
- start Clover;
- insert the second USB containing the ZimaOS installer;
- choose the entry equivalent to Boot ZimaOS from EFI;
- complete the normal installer prompts;
- remove the installer USB when installation finishes;
- attempt to boot the installed ZimaOS through Clover.
A 2026 User Reported That the Installed System Did Not Boot
On May 25, 2026, a community user said the method did not work for them because after installation and reboot the Legacy BIOS PC would not start the installed operating system.
That is not a minor detail. A method that can launch the installer but cannot reliably chain-load the installed system is not a complete installation solution.
Installer Boot and Installed-System Boot Are Separate Tests
Clover presenting the USB installer as an EFI target proves only the first stage. After installation, Clover must also find and boot the EFI environment on the destination disk on every restart.
Storage-controller behavior, partition layout, Clover configuration, or destination-disk EFI files can affect that second stage.
When This Workaround Makes Sense
- the machine genuinely has no usable UEFI mode;
- you accept an experimental boot chain;
- the system is not yet holding irreplaceable data;
- you can test repeated cold boots before trusting it as a NAS.
Legacy BIOS FAQ
Is Legacy BIOS officially supported by the current ZimaOS installer?
No. Current installation guidance requires UEFI mode.
Who created the Clover workaround?
The forum post credits Albert Gutiérrez Muñoz and was shared by Zima-Giorgio for community testing.
Does booting the installer prove the final system will boot?
No. A later user reported installation completed but the installed system would not boot after restart.
