feat: Fake BIOS version for testing the BIOS update item

- run.sh: BIOS_VERSION=... reports that BIOS version to the guest (SMBIOS type 0).
- Skill: testing the BIOS item with WIZARD_BIOS_DRY_RUN=1, and the wizard's menu loop.

.claude/skills/cachyos-vm-testing/SKILL.md

@@ -224,6 +224,19 @@ autologin, then (all passed last run; `scripts/vmstate.sh` after every step):
 8. Conversion off: single user auto-unticked, plasmalogin `[Autologin]` back to CachyOS's `Session=plasma`, journals empty.
 9. Remove the test autologin file, reboot: normal login screen.
 
+## BIOS update item
+
+Only shown with `--fremont`, and only tickable when the guest's BIOS version
+differs from Valve's newest. Fake an older one with
+`BIOS_VERSION=F7F0107 ./run.sh --fremont` (SMBIOS type 0; `vmreset.sh` passes
+the environment through). fwupd correctly refuses the firmware in the VM
+("not for this machine's hardware"), so walk the whole flow with
+`WIZARD_BIOS_DRY_RUN=1` (skips only that check, never flashes). Scripted:
+`printf '6\n\ny\ny\nUPDATE\n\nq\n' | WIZARD_BIOS_DRY_RUN=1 /mnt/setup-gamescope-boot.sh`.
+
+The wizard loops back to the menu after every run (Enter, or `m`/`r` when a
+restart is needed) until `q`; scripted input that runs out ends it like `q`.
+
 ## Visual checks
 
 `scripts/vmshot.sh <out.png>` does the below. Starting `spectacle` straight

CHANGELOG.md

@@ -24,7 +24,12 @@ Watchable test runs and the lessons from testing cachyos-gamescope-boot 0.7.0
     the conversion/single-user coupling, the repo mount lost on reboot,
     re-applying the conversion resets the session to gamescope, the new
     theme and LED checks in the test matrix, and the broken mirror workaround.
-- **docs: Changelog**
+- `3733f94` **docs: Changelog**
+- **feat: Fake BIOS version for testing the BIOS update item**
+  - `BIOS_VERSION=F7F0107 ./run.sh ...` makes the guest report that BIOS
+    version (SMBIOS type 0), so the wizard offers the update.
+  - Skill: testing the BIOS item with `WIZARD_BIOS_DRY_RUN=1`, and the
+    wizard's menu loop.
 
 ## 0.1.1 - 2026-09-23
 

run.sh

@@ -6,6 +6,8 @@
 #     --vulkan   expose Vulkan to the guest (venus; needed by gamescope, can be unstable)
 #     --fremont  report the Valve Steam Machine's DMI data (for testing the wizard)
 # REPO defaults to $HOME/projects/cachyos-gamescope-boot.
+# BIOS_VERSION=F7F0107 makes the guest report that BIOS version (DMI), e.g.
+# to test the wizard's BIOS update item; the firmware itself doesn't change.
 # The repo is shared into the guest; mount it there with:
 #   sudo mount -t 9p -o trans=virtio,version=9p2000.L repo /mnt
 # First-time SSH setup, inside the guest:
@@ -17,13 +19,14 @@ repo="${REPO:-$HOME/projects/cachyos-gamescope-boot}"
 cdrom=()
 smbios=()
 gpu=virtio-vga-gl,xres=1920,yres=1080
+[[ -n "${BIOS_VERSION:-}" ]] && smbios+=(-smbios "type=0,version=$BIOS_VERSION")
 for arg in "$@"; do
     case "$arg" in
         install)  cdrom=(-cdrom cachyos.iso -boot d) ;;
         --nvidia) export __NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia \
                          __EGL_VENDOR_LIBRARY_FILENAMES=/usr/share/glvnd/egl_vendor.d/10_nvidia.json ;;
         --vulkan) gpu+=,hostmem=4G,blob=true,venus=true ;;
-        --fremont) smbios=(-smbios type=1,manufacturer=Valve,product=Fremont -smbios type=2,manufacturer=Valve,product=Fremont) ;;
+        --fremont) smbios+=(-smbios type=1,manufacturer=Valve,product=Fremont -smbios type=2,manufacturer=Valve,product=Fremont) ;;
         *) echo "unknown argument: $arg" >&2; exit 1 ;;
     esac
 done