Scrammy

System Specs: Dell T7810 Dual Xeon E5-2695 v3 128 GB ECC RDIMM RAM (2x64 GB) I encountered freezing and rebooting issues when attempting to boot Unraid 7.0.0 RC2 on my system. Based on the errors during boot, I modified my syslinux.cfg file to include specific kernel parameters, which resolved the issue. default menu.c32 menu title Lime Technology, Inc. prompt 0 timeout 50 label Unraid OS menu default kernel /bzimage append initrd=/bzroot intremap=no_x2apic_optout mce=off clocksource=hpet label Unraid OS GUI Mode kernel /bzimage append initrd=/bzroot,/bzroot-gui intremap=no_x2apic_optout mce=off clocksource=hpet label Unraid OS Safe Mode (no plugins, no GUI) kernel /bzimage append initrd=/bzroot unraidsafemode intremap=no_x2apic_optout mce=off clocksource=hpet label Unraid OS GUI Safe Mode (no plugins) kernel /bzimage append initrd=/bzroot,/bzroot-gui unraidsafemode intremap=no_x2apic_optout mce=off clocksource=hpet label Memtest86+ kernel /memtest Why These Kernel Parameters? 1. intremap=no_x2apic_optout Purpose: Disables x2APIC IRQ remapping to prevent issues with incomplete BIOS support. Error Addressed: DMAR-IR: Enabled IRQ remapping in x2apic mode x2apic IRQ remapping doesn’t support interrupt remapping 2. mce=off Purpose: Suppresses Machine Check Exceptions (MCE) temporarily to allow the system to boot. Error Addressed: mce: [Hardware Error]: CPU 0: Machine Check Exception: 5 Bank 0: f2000000000a0005 mce: [Hardware Error]: Processor context corrupt 3. clocksource=hpet Purpose: Forces the use of HPET (High Precision Event Timer) as the system clocksource, which is more stable on problematic hardware. Error Addressed: TSC 8bc41149e62f TIME 1735736396 SOCKET 0 APIC 0 microcode de 49 Detailed Error Analysis: Error: x2APIC IRQ Remapping Cause: The system initializes Intel VT-d (IOMMU) and IRQ remapping, but incomplete BIOS support for x2APIC causes instability. Solution: Disable x2APIC remapping via the intremap=no_x2apic_optout parameter. Error: Machine Check Exception (MCE) Cause: Low-level CPU errors due to microcode incompatibility, BIOS/kernel misconfiguration, or hardware instability. Solution: Temporarily suppress MCE with mce=off to isolate the issue. Update BIOS and microcode as a long-term fix. Error: Unstable TSC Clocksource Cause: Timing issues common on multi-socket systems like the Dell T7810. Solution: Force a stable clocksource with clocksource=hpet. Final Notes: If you're facing similar issues, try adding these parameters one at a time to narrow down the root cause. For me, adding all three resolved the problem. If this helps you or you have further insights, feel free to share!