Stop shipping a second kernel nobody boots

The live ISO boots one kernel for every machine, and after the preceding commit
that kernel is linux-t2. Stock linux is then a second kernel nobody boots, plus
its own archiso initramfs, copied into both the ISO tree and the
size-constrained FAT EFI image — about 147MB.

It could not simply be deleted: releng's broadcom-wl hard-depends on linux and
is the only releng package that does, so pacman would pull the kernel back in.

broadcom-wl is a prebuilt module for stock linux and cannot load on linux-t2.
It has kept working until now only because of the bug the preceding commit
fixes — the ISO has been booting stock all along — so it is booting T2 that
takes it away, not this commit. Dropping the package only stops shipping
something that can no longer load. Nothing in the offline install needs Wi-Fi
in the live environment.

Both packages stay in the offline mirror and this changes nothing about
installed systems: linux comes from builder/archinstall.packages and remains
what configurator's detect_kernel picks for every machine that is not a T2 Mac,
and broadcom-wl comes from omarchy-other.packages, so install/hardware/
fix-bcm43xx.sh can still install it offline on BCM4360/BCM4331 MacBooks.

The removal is anchored so linux-t2, linux-firmware, linux-firmware-marvell and
linux-atm are untouched; verified against releng's real list.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

builder/build-iso.sh

@@ -116,6 +116,19 @@ cp "/tmp/$NODE_FILENAME" "$build_cache_dir/airootfs/opt/packages/"
 arch_packages=(linux-t2 git gum jq openssl plymouth python-terminaltexteffects tzupdate omarchy-keyring "$OMARCHY_SETTINGS_PACKAGE" lvm2 cryptsetup parted)
 printf '%s\n' "${arch_packages[@]}" >> "$build_cache_dir/packages.x86_64"
 
+# The live ISO boots linux-t2 (see airootfs/etc/mkinitcpio.d/linux-t2.preset), so
+# stock linux is a second kernel nobody boots: ~147MB of ISO, plus its own archiso
+# initramfs, copied into both the ISO tree and the size-constrained FAT EFI image.
+#
+# It cannot just be deleted — releng's broadcom-wl hard-depends on it, and it is
+# the only releng package that does, so pacman would drag the kernel straight back
+# in. broadcom-wl is a prebuilt module for stock linux and cannot load on the
+# kernel we boot, so it has done nothing since we started booting T2 anyway. The
+# install is entirely offline and the live environment needs no Wi-Fi driver.
+#
+# Anchored so linux-t2 and linux-firmware are untouched.
+sed -i -E '/^(linux|broadcom-wl)$/d' "$build_cache_dir/packages.x86_64"
+
 # Build the offline mirror: everything pacstrap might want during the target
 # install. With --local-source, the omarchy* packages we just built are
 # already in the mirror and we filter them out below. Without it, pacman -Syw

configs/airootfs/etc/mkinitcpio.d/linux-t2.preset

@@ -0,0 +1,18 @@
+# mkinitcpio preset file for the 'linux-t2' package on archiso
+#
+# The filename is the pkgbase, and that is load-bearing. Kernel packages ship
+# nothing in /boot — they only install usr/lib/modules/<kver>/vmlinuz — so
+# mkinitcpio's alpm hook sources /etc/mkinitcpio.d/<pkgbase>.preset and copies
+# THAT package's kernel to whatever ALL_kver names (is_kernelcopy in
+# /usr/share/libalpm/scripts/mkinitcpio). Named linux.preset, this pointed the
+# stock kernel at the T2 filenames, so the ISO booted stock Arch while every
+# boot entry said linux-t2 and T2 Macs got no keyboard or trackpad.
+#
+# releng ships its own linux.preset for the stock kernel; leave it alone.
+
+PRESETS=('archiso')
+
+ALL_kver='/boot/vmlinuz-linux-t2'
+archiso_config='/etc/mkinitcpio.conf.d/archiso.conf'
+
+archiso_image="/boot/initramfs-linux-t2.img"

configs/airootfs/etc/mkinitcpio.d/linux.preset

@@ -1,9 +0,0 @@
-# mkinitcpio preset file for the 'linux' package on archiso
-
-PRESETS=('archiso')
-
-ALL_kver='/boot/vmlinuz-linux-t2'
-archiso_config='/etc/mkinitcpio.conf.d/archiso.conf'
-
-archiso_image="/boot/initramfs-linux-t2.img"
-

plans/aarch64-support.md

@@ -76,9 +76,9 @@ aarch64 has no BIOS — only UEFI. Drop the syslinux path entirely on ARM.
 
 The cleanest cut: keep one `grub.cfg` shared, strip the x86 shell/memtest fragments at build time when `OMARCHY_ARCH=aarch64`. Don't fork the file.
 
-### 6. mkinitcpio preset — `configs/airootfs/etc/mkinitcpio.d/linux.preset`
+### 6. mkinitcpio preset — `configs/airootfs/etc/mkinitcpio.d/linux-t2.preset`
 
-References `vmlinuz-linux-t2` and `initramfs-linux-t2.img` (lines 5, 8). For aarch64, swap to `vmlinuz-linux` / `initramfs-linux.img`. Generate the file at build time from a template, keyed on arch.
+Names `vmlinuz-linux-t2` and `initramfs-linux-t2.img`. The filename is the pkgbase and the alpm hook keys off it, so aarch64 does not rename this file — it simply does not ship it, and releng's own `linux.preset` covers the stock kernel. Drop `linux-t2` from `arch_packages` on aarch64 and the boot entries point at `vmlinuz-linux` / `initramfs-linux.img`.
 
 ### 7. Configurator — `configs/airootfs/root/configurator`
 
@@ -145,7 +145,7 @@ Code:
 - `configs/efiboot/loader/loader.conf` — per-arch default entry
 - `configs/efiboot/loader/entries/01-archiso-x86_64-linux.conf` — generate aarch64 sibling at build time
 - `configs/grub/grub.cfg`, `loopback.cfg` — strip x86-only fragments on aarch64
-- `configs/airootfs/etc/mkinitcpio.d/linux.preset` — template by arch (drop linux-t2 on aarch64)
+- `configs/airootfs/etc/mkinitcpio.d/linux-t2.preset` — omit on aarch64 (drop linux-t2 there; releng's linux.preset covers the stock kernel)
 - `configs/airootfs/root/configurator` — branch archinstall JSON mirror list on `uname -m`; optionally guard lspci T2 probe
 - `.github/workflows/nightly-build.yml` — matrix x86_64/aarch64