diff --git a/install.sh b/install.sh
index 4d0bd5c..5631f84 100755
--- a/install.sh
+++ b/install.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -Eeuo pipefail
 
-INSTALL_VERSION=4
+INSTALL_VERSION=5
 ACTION=install
 case "${1:-}" in
     '') ;;
@@ -174,7 +174,7 @@ deploy_files() {
     local php_version
     log "Deploying Pivilion files"
     install -d -m 0755 /usr/local/lib/pivilion /usr/local/bin /etc/systemd/system /etc/tor/torrc.d /etc/profile.d /var/lib/pivilion
-    install -m 0644 "$SOURCE_DIR/usr/local/lib/pivilion/common.sh" /usr/local/lib/pivilion/common.sh
+    install -m 0644 "$SOURCE_DIR/usr/local/lib/pivilion/common.sh" "$SOURCE_DIR/usr/local/lib/pivilion/hostname.sh" /usr/local/lib/pivilion/
     install -m 0755 "$SOURCE_DIR/usr/local/lib/pivilion/mode.sh" "$SOURCE_DIR/usr/local/lib/pivilion/config-sync.sh" "$SOURCE_DIR/usr/local/lib/pivilion/diagnose.sh" \
         "$SOURCE_DIR/usr/local/lib/pivilion/issue-banner.sh" /usr/local/lib/pivilion/
     install -m 0755 "$SOURCE_DIR"/usr/local/bin/* /usr/local/bin/
@@ -319,7 +319,7 @@ check_install() {
     local failed=0 file
     for file in /etc/pivilion.defaults /var/lib/pivilion/install-state /etc/issue.d/90-pivilion.issue \
         /usr/local/lib/pivilion/common.sh /usr/local/lib/pivilion/mode.sh /usr/local/lib/pivilion/diagnose.sh \
-        /usr/local/lib/pivilion/config-sync.sh \
+        /usr/local/lib/pivilion/config-sync.sh /usr/local/lib/pivilion/hostname.sh \
         /usr/local/lib/pivilion/issue-banner.sh /etc/systemd/system/pivilion-mode.service \
         /etc/systemd/system/pivilion-config.service /etc/systemd/system/pivilion-login-banner.service; do
         if [ ! -e "$file" ]; then echo "Missing: $file" >&2; failed=1; fi
diff --git a/tests/run.sh b/tests/run.sh
index e0409c7..d3bcaac 100755
--- a/tests/run.sh
+++ b/tests/run.sh
@@ -62,6 +62,8 @@ boot_config_contract() {
     grep -q 'pivilion_boot_config_path' "$ROOT/usr/local/lib/pivilion/config-sync.sh" &&
         grep -q 'pivilion.conf.last-good' "$ROOT/usr/local/lib/pivilion/config-sync.sh" &&
         grep -q 'derive_psk' "$ROOT/usr/local/lib/pivilion/config-sync.sh" &&
+        grep -q 'pivilion_apply_hostname' "$ROOT/usr/local/lib/pivilion/config-sync.sh" &&
+        ! grep -R -q --include='*.sh' --include='*.service' 'hostnamectl' "$ROOT/install.sh" "$ROOT/usr" "$ROOT/etc" &&
         grep -q 'Before=.*NetworkManager' "$ROOT/etc/systemd/system/pivilion-config.service" &&
         grep -q 'config-sync.sh set PIVILION_MODE' "$ROOT/usr/local/bin/hotspot" &&
         grep -q 'config-sync.sh set-wifi' "$ROOT/usr/local/bin/pikey"
@@ -83,6 +85,7 @@ shellcheck_scripts() {
 }
 
 run "configuration and state fixtures" "$ROOT/tests/test-common.sh"
+run "early-boot hostname application" "$ROOT/tests/test-hostname.sh"
 run "shell syntax" shell_syntax
 run "PHP syntax" php_syntax
 run "systemd unit syntax" systemd_syntax
diff --git a/tests/test-hostname.sh b/tests/test-hostname.sh
new file mode 100755
index 0000000..72397cc
--- /dev/null
+++ b/tests/test-hostname.sh
@@ -0,0 +1,55 @@
+#!/bin/bash
+set -euo pipefail
+
+ROOT=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
+TMP=$(mktemp -d)
+trap 'rm -rf "$TMP"' EXIT
+
+export PIVILION_HOSTNAME_FILE="$TMP/hostname"
+export PIVILION_HOSTS_FILE="$TMP/hosts"
+export PIVILION_HOSTNAME_COMMAND="$TMP/hostname-command"
+export MOCK_HOSTNAME_STATE="$TMP/kernel-hostname"
+export MOCK_HOSTNAME_CALLS="$TMP/hostname-calls"
+
+cat > "$PIVILION_HOSTS_FILE" <<'EOF'
+127.0.0.1 localhost
+127.0.1.1 old-name old-alias
+192.0.2.1 example.test
+127.0.1.1 stale-duplicate
+EOF
+printf 'old-name\n' > "$PIVILION_HOSTNAME_FILE"
+printf 'old-name\n' > "$MOCK_HOSTNAME_STATE"
+
+cat > "$PIVILION_HOSTNAME_COMMAND" <<'EOF'
+#!/bin/sh
+if [ "${1:-}" = -s ]; then cat "$MOCK_HOSTNAME_STATE"; exit 0; fi
+printf '%s\n' "$1" > "$MOCK_HOSTNAME_STATE"
+printf '%s\n' "$1" >> "$MOCK_HOSTNAME_CALLS"
+EOF
+chmod +x "$PIVILION_HOSTNAME_COMMAND"
+
+source "$ROOT/usr/local/lib/pivilion/hostname.sh"
+
+for mode in hotspot onion; do
+    name="pivilion-$mode"
+    pivilion_apply_hostname "$name"
+    [ "$(cat "$PIVILION_HOSTNAME_FILE")" = "$name" ]
+    [ "$(awk '$1 == "127.0.1.1" { print $2 }' "$PIVILION_HOSTS_FILE")" = "$name" ]
+    [ "$(awk '$1 == "127.0.1.1" { count++ } END { print count+0 }' "$PIVILION_HOSTS_FILE")" -eq 1 ]
+    [ "$("$PIVILION_HOSTNAME_COMMAND" -s)" = "$name" ]
+
+    before=$(sha256sum "$PIVILION_HOSTNAME_FILE" "$PIVILION_HOSTS_FILE")
+    inodes=$(stat -c '%i' "$PIVILION_HOSTNAME_FILE" "$PIVILION_HOSTS_FILE")
+    calls=$(wc -l < "$MOCK_HOSTNAME_CALLS")
+    pivilion_apply_hostname "$name"
+    [ "$before" = "$(sha256sum "$PIVILION_HOSTNAME_FILE" "$PIVILION_HOSTS_FILE")" ]
+    [ "$inodes" = "$(stat -c '%i' "$PIVILION_HOSTNAME_FILE" "$PIVILION_HOSTS_FILE")" ]
+    [ "$calls" -eq "$(wc -l < "$MOCK_HOSTNAME_CALLS")" ]
+done
+
+grep -Fqx '192.0.2.1 example.test' "$PIVILION_HOSTS_FILE"
+
+PIVILION_HOSTNAME_FILE="$TMP/missing/hostname"
+export PIVILION_HOSTNAME_FILE
+if pivilion_apply_hostname broken >"$TMP/failure.out" 2>&1; then exit 1; fi
+grep -q 'Could not create a temporary file' "$TMP/failure.out"
diff --git a/usr/local/lib/pivilion/config-sync.sh b/usr/local/lib/pivilion/config-sync.sh
index 0487043..fabf56d 100644
--- a/usr/local/lib/pivilion/config-sync.sh
+++ b/usr/local/lib/pivilion/config-sync.sh
@@ -2,6 +2,7 @@
 set -Eeuo pipefail
 
 source "${PIVILION_COMMON_PATH:-/usr/local/lib/pivilion/common.sh}"
+source "${PIVILION_HOSTNAME_LIB_PATH:-$(dirname -- "${BASH_SOURCE[0]}")/hostname.sh}"
 pivilion_require_root
 
 BOOT_ROOT=$(pivilion_boot_root)
@@ -189,7 +190,10 @@ migrate_paths() {
 apply_runtime() {
     local php_version post_mb escaped_ssid
     migrate_paths
-    if [ "$(hostname -s)" != "$PIVILION_HOSTNAME" ] && command -v hostnamectl >/dev/null 2>&1; then hostnamectl set-hostname "$PIVILION_HOSTNAME"; fi
+    if ! pivilion_apply_hostname "$PIVILION_HOSTNAME"; then
+        fail_boot "Failed to apply hostname '$PIVILION_HOSTNAME' without D-Bus"
+        return "$PIVILION_E_CONFIG"
+    fi
     command -v iw >/dev/null 2>&1 && iw reg set "$PIVILION_WIFI_COUNTRY" 2>/dev/null || true
     if [ -n "$PIVILION_WIFI_SSID" ] && [ -n "$PIVILION_WIFI_PSK" ]; then
         if command -v nmcli >/dev/null 2>&1 && { systemctl is-enabled --quiet NetworkManager 2>/dev/null || systemctl is-active --quiet NetworkManager 2>/dev/null; }; then
diff --git a/usr/local/lib/pivilion/hostname.sh b/usr/local/lib/pivilion/hostname.sh
new file mode 100644
index 0000000..cda681f
--- /dev/null
+++ b/usr/local/lib/pivilion/hostname.sh
@@ -0,0 +1,64 @@
+#!/bin/bash
+
+# Apply a hostname without systemd-hostnamed. This file is also sourced by the
+# test suite, so paths and the hostname command may be redirected there.
+pivilion_apply_hostname() {
+    local hostname=$1
+    local hostname_file=${PIVILION_HOSTNAME_FILE:-/etc/hostname}
+    local hosts_file=${PIVILION_HOSTS_FILE:-/etc/hosts}
+    local hostname_command=${PIVILION_HOSTNAME_COMMAND:-/bin/hostname}
+    local tmp current
+
+    tmp=$(mktemp "$(dirname "$hostname_file")/.pivilion-hostname.XXXXXX") || {
+        echo "Could not create a temporary file for $hostname_file" >&2
+        return 1
+    }
+    printf '%s\n' "$hostname" > "$tmp" && chmod 0644 "$tmp" || {
+        rm -f "$tmp"
+        echo "Could not prepare $hostname_file for hostname '$hostname'" >&2
+        return 1
+    }
+    if [ -r "$hostname_file" ] && cmp -s "$tmp" "$hostname_file"; then
+        rm -f "$tmp"
+    elif ! mv -f "$tmp" "$hostname_file"; then
+        rm -f "$tmp"
+        echo "Could not atomically write hostname '$hostname' to $hostname_file" >&2
+        return 1
+    fi
+
+    tmp=$(mktemp "$(dirname "$hosts_file")/.pivilion-hosts.XXXXXX") || {
+        echo "Could not create a temporary file for $hosts_file" >&2
+        return 1
+    }
+    awk -v hostname="$hostname" '
+        $1 == "127.0.1.1" { if (!written++) print "127.0.1.1\t" hostname; next }
+        { print }
+        END { if (!written) print "127.0.1.1\t" hostname }
+    ' "$hosts_file" > "$tmp" 2>/dev/null || {
+        rm -f "$tmp"
+        echo "Could not update the 127.0.1.1 entry in $hosts_file" >&2
+        return 1
+    }
+    chmod 0644 "$tmp" || {
+        rm -f "$tmp"
+        echo "Could not prepare the updated $hosts_file" >&2
+        return 1
+    }
+    if [ -r "$hosts_file" ] && cmp -s "$tmp" "$hosts_file"; then
+        rm -f "$tmp"
+    elif ! mv -f "$tmp" "$hosts_file"; then
+        rm -f "$tmp"
+        echo "Could not atomically update the 127.0.1.1 entry in $hosts_file" >&2
+        return 1
+    fi
+
+    [ -x "$hostname_command" ] || {
+        echo "Cannot set the running hostname: $hostname_command is not executable" >&2
+        return 1
+    }
+    current=$($hostname_command -s 2>/dev/null || true)
+    if [ "$current" != "$hostname" ] && ! "$hostname_command" "$hostname"; then
+        echo "Could not set the running kernel hostname to '$hostname' with $hostname_command" >&2
+        return 1
+    fi
+}