The BC-250 enumerates as /sys/class/drm/card0 on a typical install (no
secondary GPU). Verified live on Fedora 43, kernel 7.0.9, PCI 1002:13fe.
Many doc snippets hardcoded card1, so copy-paste failed on a stock single-
GPU board.
Replaced /sys/class/drm/card1/ with /sys/class/drm/card0/ across:
bios/overclocking.md, bios/vram.md, drivers/radv.md,
getting-started/quick-start.md, linux/{arch,bazzite,cachyos,debian,fedora}.md,
reference/quick-reference.md, system/{governor,sensors}.md,
troubleshooting/{boot,display,performance,stability}.md.
Existing card0-vs-card1 disclaimers preserved at governor.md L166/L503,
quick-start.md L78, bazzite.md L104, kernel.md L222 (and quick-reference.md
intro rewritten to lead with card0 + note the iGPU edge case).
gpu_busy_percent returns "Operation not supported" on BC-250 (the amdgpu
driver does not populate that sysfs file for this hardware; same root cause
as the MangoHud 655% bug). The Quick Diagnostics, Low FPS, and gaming
performance checklist sections all told users to watch this file in a
loop, which on a real BC-250 spams cat errors.
Replaced with watch on pp_dpm_sclk, which does work and shows the actual
DPM level with the * marker. Cross-referenced the MangoHud admonition for
the root cause explanation. Also switched card1 to card0 in those snippets
to match the actual enumeration on a stock BC-250 install.
Root cause reproduced on the live BC-250 (Fedora 43 / kernel 7.0.9-105.fc43,
MangoHud 0.8.2). The amdgpu driver does not populate the GPU activity field
of /sys/.../gpu_metrics for this hardware: bytes 0x1C-0x1D stay at 0xFFFF,
which MangoHud reads as 65535 and divides by 100, giving the famous 655%
load reading.
Fix verified on the same board: cyan-skillfish-governor-smu (smu branch)
bind-mounts a writable tmpfs file over gpu_metrics and writes a sampled
activity value (busy-flag method) into byte 0x1C every cycle. With governor
stopped, bytes 0x1C-0x1D read 0xFFFF. With governor running, the same
bytes read 0x0000 at idle. Both states confirmed via dd skip=28 count=4.
Bind mount visible in /proc/self/mountinfo while the service is active.
Mechanism verified in upstream source at src/gpu_usage_fix.rs.
The relevant config keys (gpu-usage.fix-metrics = true,
gpu-usage.method = busy-flag) are upstream defaults, so installing and
enabling the service is sufficient. No MangoHud config change required.
The active upstream of cyan-skillfish-governor is filippor/cyan-skillfish-governor
(v0.4.6, May 2026, 27 stars), not Magnap/cyan-skillfish-governor (v0.1.3,
Aug 2025, 12 stars). Several install paths in the docs were pointing readers
at Magnap releases and telling them to wget a .deb that no longer exists in
the upstream release pipeline.
- system/governor.md: TT section repo link, SMU feature list (drop .deb/Nix
claims, mention tarball + COPR + AUR), Option 2 rewritten as tarball
install with scripts/install.sh, Option 3 build-from-source link updated.
- linux/cachyos.md: build-from-source link updated.
- linux/debian.md: Option 1 rewritten as tarball install.
- troubleshooting/performance.md: Debian quick-install line rewritten.
Magnap is preserved as historical credit in two developer-attribution lines
(SMU was originally Magnap, filippor maintains the active fork).
A common BC-250 testing pitfall on headless boxes: glmark2 --off-screen
silently falls back to LLVMpipe (CPU software rendering) when no display
is attached. GPU never gets loaded, gpu_busy_percent stays 0, governor
never boosts, and the next 3 hours go into investigating a phantom
governor bug.
Adds a Testing GPU Load on a Headless BC-250 subsection to the
Performance Monitoring & Benchmarking section with:
- explicit warning about the glmark2 --off-screen trap
- recommended real-GPU-load alternatives (clpeak, llama-bench, vkmark)
- a one-liner to verify SCLK and power are actually climbing before
drawing any conclusions from a load test
Derived from a maintainer investigation that lost an evening to exactly
this issue.
Key fixes:
- nct6687 for fan control (not nct6683 which is read-only)
- GPU is card1 not card0 in all sysfs paths
- Fan on pwm2/fan2 (Pump Fan header), not pwm1
- Vulkan 1.4.328 (not 1.3), Mesa 25.3.6 (not 25.2.4)
- cpupower doesn't work on BC-250 (removed recommendations)
- pp_dmu_clock -> pp_dpm_mclk
- ACPI fix marked as optional/experimental (not essential)
- amdgpu.sg_display=0 only needed for kernels < 6.10
- GPU voltage range 700-1129 mV (from OD_RANGE)
- Added CoolerControl installation instructions
- Expanded sensors.md with proper nct6687 setup guide
- display.md: DisplayLink unreliable (latency, no game mode), DP MST max 2 screens
- cooling.md: 3 heatsink variants (QR code = 9-row), thermal pads 1.5mm front/2.0mm back
- distributions.md: Ubuntu 26.04 daily server ISO works out of box
- radv.md: LLM headless mode tip (~14.2GB available VRAM, headless saves ~800MB)
- stability.md: P5.00 BIOS more susceptible to bricking from memory timing;
tREF most rewarding timing, GDDR6 ICs are bottom-binned Micron
- Replace oberon-governor with cyan-skillfish-governor-tt as default across
bazzite, debian, arch, cachyos, fedora, power, quick-reference, display,
performance, radv, and stability pages (oberon remains documented as legacy)
- Add "Black Screen on GPU Reset (Governor Running)" section to
troubleshooting/stability.md (source: Discord user nohanmv, Feb 26)
- Remove AI filler: "comprehensive" from index/sensors, unverifiable stats
(3500+ members, 100+ solutions, 30+ games, 9716/7000+ messages analyzed,
90%/95% success rates)
- Remove unverifiable 8K @60Hz display claim
- Update governor config examples from oberon YAML format to
cyan-skillfish-governor-tt TOML format
- Normalize community links to point to filippor/cyan-skillfish-governor
Update default governor commands to cyan-skillfish-governor-tt in
quick-reference cheatsheet and stability troubleshooting diagnostic section.
Oberon-governor noted as alternative where applicable.
- Remove oberon-governor as "Option 1 (Recommended)" from performance
troubleshooting, replace with cyan-skillfish-governor-tt
- Remove stale RADV_DEBUG=nocompute advice (deprecated in Mesa 25.1+)
- Update checklist and system info commands to reference current governor
- Remove unverifiable PS5 comparison percentages from gaming page
- cyan-skillfish-governor → cyan-skillfish-governor-tt (service names and
config paths throughout overclocking, power, and troubleshooting docs)
- Update TTM page pool parameters to 3959290 for correct 14.75GB VRAM
- Add SMU governor variant to AUR install instructions
- Clarify 700mV minimum voltage behavior (locks GPU to 1500MHz)
- Update SMU governor description from "emerging" to established
- Fix Oberon Governor URL from TuxThePenguin0 to mothenjoyer69 in power.md
- Add zswap as alternative to zram in performance troubleshooting, with
Bazzite-specific setup commands from community Discord (Dec 2025)
The broken kernel range is 6.17.8-6.17.10, not 6.17.8+ — kernel 6.17.11+
has the fix applied. Updated 11 files to use the precise range and added
6.17.11+/6.18.x as recommended alternatives. Also added a warning about
6.19.x PCIe issues reported in March 2026.
- Replace deprecated fedora-setup.sh with modern manual installation steps
* Mesa 25.1+ now included in Fedora 43 repos (no COPR needed)
* Governor installation via @exotic-soc/oberon-governor COPR
* Updated in quick-start.md and troubleshooting/display.md
- Fix idle power specifications in prerequisites.md
* Corrected minimum idle power: 70-85W (was incorrectly 50-80W)
* Added note about GPU freq patch increasing max power to 250W+
- Update footer GitHub link to elektricM/amd-bc250-docs
* Changed from mothenjoyer69/bc250-documentation
* Updated in mkdocs.yml and introduction.md
All changes verified with mkdocs build --strict (no warnings).
Applied comprehensive corrections from Discord community (DeathStalker, Astrocast,
and others) to fix inaccuracies, remove outdated procedures, and improve readability.
CRITICAL SAFETY FIXES:
- IOMMU: Changed from "optional" to "MUST disable" across all docs
- Removed dangerous `amd_iommu=on` kernel parameter (causes crashes)
- Added danger warnings that IOMMU is broken on BC-250
BIOS & VRAM FIXES:
- Fixed BIOS flashing guide: removed fake "ZIP file" references
- Added link to actual flasher utility (separate from ROM download)
- Removed made-up Windows utility steps, added real ASRock method
- Removed AMIBCP/Smokeless section (not used, P5.00_clv has all unlocked)
- VRAM docs: reduced verbosity by 40%, emphasized 512MB is DYNAMIC
- Added ZRAM conflict warning (crashes in RDR2 with dynamic VRAM)
COOLING & HARDWARE:
- Removed impractical fin cutting/screwing instructions
- Removed J4003 header references (not for normal users)
- Added tower cooler downside (must cool VRAMs separately)
- Static pressure already correct at 6.9 mm H2O
LINUX DISTRIBUTION UPDATES:
- Fedora: Removed outdated setup script, Mesa 25.1 now in repos
- Fedora: nomodeset no longer needed on 42/43 with working kernels
- Bazzite: Removed "on steroids" section (patch included by default)
- CachyOS: Simplified from custom ISO to standard installation
- Updated KDE vs GNOME: GNOME recommended for stability (6 changes)
- SteamOS/Ubuntu: Already added in previous commit (verified)
GOVERNOR & DRIVERS:
- Prioritized COPR installation over building from source
- Added @exotic-soc/oberon-governor and filippor/bazzite repos
- Display adapters: Now recommend PASSIVE (audio works) over active
IMPOSSIBLE FEATURES REMOVED:
- Fortnite: Clarified it cannot run (Easy Anti-Cheat)
- ROCm training: Corrected to "experimental/limited" (doesn't work)
Desktop Environment: GNOME now recommended over KDE for stability
(KDE had Qt RDSEED bug, now fixed but GNOME more tested)
Files modified: 14
Community credits: DeathStalker, Astrocast, legodude
Corrected kernel compatibility throughout documentation based on community feedback:
PREVIOUS (INCORRECT):
- Stated 'avoid kernel 6.15+' entirely
- Recommended only 6.12-6.14 LTS
CORRECTED:
- 6.15.0-6.15.6: Broken (GPU init fails)
- 6.15.7-6.17.7: Works (recommended, kernel support fixed)
- 6.17.8+: Broken again (GPU driver issues)
- 6.12-6.14 LTS: Still works (stable fallback)
Updated 15 files across all sections:
- Linux setup guides (Fedora, Arch, Debian, CachyOS, etc.)
- Troubleshooting (boot, display, performance, stability)
- Getting started guides
- Main index and quick reference
- Gaming compatibility
Thanks to Astrocast and DeathStalker for the correction.
