For years, running OS/2-based operating systems on modern computers required a Traditional BIOS or a Compatibility Support Module (CSM) firmware layer. As hardware manufacturers phased out CSM, legacy operating systems faced an existential compatibility wall.

The 5.1 release is a landmark milestone. It introduces support for modern UEFI firmware and GPT partitioning schemes, allowing the OS to install on hardware that has completely abandoned the classic legacy BIOS. Key Breakthroughs in the 5.1 ISO 1. Native UEFI Support

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