Choose your kernel

Outcome: Select the USB image's Linux entry for the widest current feature coverage, or LexiKernel to test the experimental Rust kernel with clear expectations.

Boot entries in the current image

Boot menu	Description	Recommended use
1 LexiKernel	Rust kernel with Linux-ABI compatibility, strict IOMMU requirements and partial device/telemetry coverage.	Testing, qualification and experiments on supported hardware.
2 LexiOS on Linux 7.4	LexiOS userland over the 7.4-rc2 Linux entry of the current USB image.	First installation, broader hardware coverage and GPU workloads.

Earlier testing images used Linux 7.3. Do not infer the kernel version from an older README or install instructions; the image build matters. An existing Linux host running the engine is not the same as running the USB appliance.

Requirements and practical differences

LexiKernel refuses to boot without an active IOMMU (Intel VT-d or AMD-Vi). Ensure IOMMU translation is enabled in firmware, a supported network device is connected and the boot medium uses xHCI USB. Refer to the hardware matrix.
LexiKernel has booted a physical Intel ThinkPad P71 and brought up network/Panel service. An AMD-IOMMU boot was qualified in a virtual machine, not yet on physical AMD hardware.
LexiKernel runs all threads of a process on one CPU, which makes its CPU inference far slower than Linux on relevant workloads. LexiKernel's own RDNA3 driver now starts a physical Radeon RX 7900 XTX (passed through to LexiKernel in a virtual machine) as far as running a command buffer from a user address space with an interrupt-delivered fence; it has not run a shader or inference yet. GPU compute under LexiKernel still relies on a Linux driver-domain guest.
System feature availability differs. LexiKernel's Panel should explicitly say unavailable with a reason for unsupported Linux services; storage-usage and CPU-usage measurement are known incomplete areas. Do not treat missing numbers as proof of success.
Secure Boot works with the development-signed image after owner certificate append; qualification of both entries was in a VM. Follow Secure Boot.
One of five current LexiKernel browser boots froze just after the console appeared; root cause unresolved.

How to decide

Need to install a model, check GPU visibility or assess stable operational coverage? Choose 2 LexiOS on Linux 7.4.
Need to test the Rust kernel? Confirm the IOMMU, USB and NIC entries on Hardware, then choose 1 LexiKernel.
At the local console read the selected kernel, signing state and Panel address. Open the Panel and check supported controls. Record unavailable messages accurately rather than forcing operations.
If a feature is missing under LexiKernel, reboot and choose the Linux entry. This changes the booted kernel; it does not make a missing driver available on LexiKernel.

Kernel controls

Choice / control	Consequence
1 LexiKernel	Attempts experimental kernel boot and refuses unsafe/unsupported IOMMU state.
2 LexiOS on Linux 7.4	Boots the image's Linux 7.4-rc2 environment, with wider driver coverage.
Secure Boot: Enabled	Requires the appropriate development certificate in firmware `db` for this image.
Panel capability: unavailable with a reason	Signals no supported kernel-side implementation; do not retry as an unauthorized mutation.

See Hardware, First Boot, Security and Troubleshooting.