diff --git a/CHANGELOG.md b/CHANGELOG.md
index bd99125..b9fe290 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,16 @@ All notable changes to RigForge are documented here. The format is based on
 
 ## [Unreleased]
 
+### Fixed
+
+- **Debian: dependency install no longer fails on `linux-tools-common` (#327).** The apt dependency
+  list named `linux-tools-common` unconditionally, but that package is Ubuntu-only — Debian ships
+  cpupower as `linux-cpupower` — and apt's install transaction is all-or-nothing, so the one unknown
+  name failed the ENTIRE install: git, build-essential and cmake never arrived either. `setup` now
+  probes with `apt-cache show` (the same guard the kernel-versioned `linux-tools-$(uname -r)`
+  package already had) and adds whichever name the distro actually ships; when neither exists it
+  warns and moves on — cpupower is a tuning aid, never worth losing the compiler toolchain over.
+
 ## [1.13.1] - 2026-08-01
 
 ### Fixed
diff --git a/rigforge.sh b/rigforge.sh
index f6fa9e0..2fefea9 100755
--- a/rigforge.sh
+++ b/rigforge.sh
@@ -738,7 +738,20 @@ _detect_pkg_manager() {
         DEP_LIST="git build-essential cmake libuv1-dev libssl-dev libhwloc-dev gettext-base python3"
         if [ "$OS_TYPE" == "Linux" ]; then
             # msr-tools (rdmsr): lets `doctor` verify the prefetcher MSR mod actually applied (#66).
-            DEP_LIST="$DEP_LIST linux-tools-common msr-tools"
+            DEP_LIST="$DEP_LIST msr-tools"
+            # cpupower's package name differs by distro: linux-tools-common on Ubuntu,
+            # linux-cpupower on Debian. apt's install transaction is all-or-nothing, so one unknown
+            # name would fail the ENTIRE dependency install — gcc/cmake included (#327). Probe with
+            # apt-cache show (same guard as the kernel-versioned package below) and add only the
+            # name this distro actually ships; when neither exists, warn and carry on — cpupower is
+            # a tuning aid, never worth losing the compiler toolchain over.
+            if apt-cache show linux-tools-common &>/dev/null; then
+                DEP_LIST="$DEP_LIST linux-tools-common"
+            elif apt-cache show linux-cpupower &>/dev/null; then
+                DEP_LIST="$DEP_LIST linux-cpupower"
+            else
+                warn "No cpupower package found (tried linux-tools-common, linux-cpupower) — skipping it. Frequency tuning via cpupower may be unavailable."
+            fi
             if apt-cache show "linux-tools-$(uname -r)" &>/dev/null; then
                 DEP_LIST="$DEP_LIST linux-tools-$(uname -r)"
             fi
diff --git a/tests/run.sh b/tests/run.sh
index 10c3d02..b01cec6 100644
--- a/tests/run.sh
+++ b/tests/run.sh
@@ -2534,6 +2534,56 @@ chmod +x "$LT"/*
     PATH="$LT" CALL_LOG="$LT/calls.log" install_dependencies </dev/null
 ) >/dev/null 2>&1
 assert_contains "apt install list includes linux-tools-<rel> (#74)" "$(cat "$LT/calls.log")" "linux-tools-6.0.0-rig"
+# The same run doubles as the Ubuntu cpupower shape (#327): apt-cache says linux-tools-common
+# exists, so it's picked and the Debian name never enters the list.
+assert_contains "Ubuntu shape: cpupower via linux-tools-common (#327)" "$(cat "$LT/calls.log")" "linux-tools-common"
+assert_absent "Ubuntu shape: linux-cpupower stays out (#327)" "$(cat "$LT/calls.log")" "linux-cpupower"
+
+# #327: cpupower's apt package is distro-dependent — linux-tools-common (Ubuntu) vs linux-cpupower
+# (Debian) — and apt's all-or-nothing transaction means one unknown name kills the ENTIRE dependency
+# install (gcc/cmake included). The probe must pick the name the distro ships, and a double miss must
+# warn without touching the toolchain install. Ubuntu shape is asserted on the #74 run above.
+echo "== unit: apt cpupower package probe — Debian / neither exists (#327) =="
+DEB="$(mktemp -d "$SANDBOX/deb327.XXXXXX")"
+printf '#!/bin/sh\nexit 1\n' >"$DEB/dpkg" # every dep "missing" -> all go to the install list
+cat >"$DEB/apt-cache" <<'EOF'
+#!/bin/sh
+# Debian trixie shape: linux-cpupower exists; linux-tools-common and linux-tools-<rel> do not.
+case "$*" in *linux-cpupower*) exit 0 ;; *) exit 1 ;; esac
+EOF
+printf '#!/bin/sh\necho "[apt-get] $*" >>"$CALL_LOG"\n' >"$DEB/apt-get"
+printf '#!/bin/sh\nwhile [ "${1#*=}" != "$1" ]; do export "$1"; shift; done\nexec "$@"\n' >"$DEB/sudo"
+printf '#!/bin/sh\necho 6.0.0-rig\n' >"$DEB/uname"
+chmod +x "$DEB"/*
+: >"$DEB/calls.log"
+(
+    source "$SCRIPT"
+    OS_TYPE=Linux REAL_USER=test
+    PATH="$DEB" CALL_LOG="$DEB/calls.log" install_dependencies </dev/null
+) >/dev/null 2>&1
+assert_contains "Debian shape: cpupower via linux-cpupower (#327)" "$(cat "$DEB/calls.log")" "linux-cpupower"
+assert_absent "Debian shape: linux-tools-common stays out (#327)" "$(cat "$DEB/calls.log")" "linux-tools-common"
+
+# Neither name exists (apt-cache always says no): warn, keep going, and the toolchain still installs.
+NC="$(mktemp -d "$SANDBOX/nc327.XXXXXX")"
+printf '#!/bin/sh\nexit 1\n' >"$NC/dpkg"
+printf '#!/bin/sh\nexit 1\n' >"$NC/apt-cache" # no cpupower package under ANY name
+printf '#!/bin/sh\necho "[apt-get] $*" >>"$CALL_LOG"\n' >"$NC/apt-get"
+printf '#!/bin/sh\nwhile [ "${1#*=}" != "$1" ]; do export "$1"; shift; done\nexec "$@"\n' >"$NC/sudo"
+printf '#!/bin/sh\necho 6.0.0-rig\n' >"$NC/uname"
+chmod +x "$NC"/*
+: >"$NC/calls.log"
+nc_out="$( (
+    source "$SCRIPT"
+    OS_TYPE=Linux REAL_USER=test
+    PATH="$NC" CALL_LOG="$NC/calls.log" install_dependencies </dev/null
+) 2>&1)"
+rc=$?
+assert_rc "no cpupower package never fails the install (#327)" "$rc" "0"
+assert_contains "warns when no cpupower package exists (#327)" "$nc_out" "No cpupower package found"
+assert_contains "toolchain still installs without a cpupower package (#327)" "$(cat "$NC/calls.log")" "build-essential"
+assert_absent "no cpupower name reaches apt when neither exists (#327)" "$(cat "$NC/calls.log")" "linux-tools-common"
+assert_absent "linux-cpupower also stays out when absent (#327)" "$(cat "$NC/calls.log")" "linux-cpupower"
 
 # check_prerequisites (the jq bootstrap) had NO test. jq is deliberately kept OFF the scenario PATH so the
 # install branch runs; each dir holds ONLY the package manager(s) under test, so `command -v` selects the