diff --git a/docs/PORTMASTER.md b/docs/PORTMASTER.md
index e7e3e09..e8c24f6 100644
--- a/docs/PORTMASTER.md
+++ b/docs/PORTMASTER.md
@@ -28,18 +28,21 @@ directory. The templates in `scripts/portmaster/` are authoritative.
 
 - `port.json` uses schema version 4, names `netfishing.zip`, and marks the
   self-contained package ready to run.
-- `NETfishing.sh` starts with `# PORTMASTER: netfishing.zip, NETfishing.sh`.
+- `NETfishing.sh` does not contain a `# PORTMASTER:` signature in the source or
+  distributable archive. HarbourMaster adds that installation marker when it
+  installs the port.
 - The executable is `netfishing/NETfishing.aarch64`.
 - The package declares AArch64, two analog sticks, GLIBC 2.28, and
   `weston_pkg_0.2.squashfs`.
 - The launcher starts GPTOKEYB with the explicit `netfishing.gptk` no-op map.
-  Every keyboard and mouse binding is disabled, leaving only PortMaster's
+  Every keyboard and mouse binding is disabled, leaving only GPTOKEYB's
   device-specific force-quit chord while Godot and NETfishing's controller
-  mapping manager handle gameplay input.
+  mapping manager handle gameplay input. The explicit map also avoids the
+  anomalous controller behavior observed on ROCKNIX without a passthrough map.
 - The launcher calls `pm_platform_helper` for the game executable after
   starting GPTOKEYB and calls `pm_finish` after the game exits.
-- New installations automatically create player data under
-  `ports/saves/netfishing/` and do not present the in-game folder picker.
+- NETfishing automatically creates player data for new installations under
+  `ports/saves/netfishing/` and does not present the in-game folder picker.
 - Existing installations with a selected data root keep that location when
   upgraded. Device-local data, configuration, and cache remain under
   `netfishing/conf/data`, `netfishing/conf/config`, and
@@ -103,15 +106,15 @@ Before upgrading an existing installation, preserve
 device. After installation:
 
 1. Confirm the installed executable and PCK hashes match the staged release.
-2. Confirm the installed launcher contains the canonical PortMaster header,
-   starts GPTOKEYB with `netfishing.gptk`, and calls
-   `pm_platform_helper` for the game executable.
+2. Confirm HarbourMaster added its `# PORTMASTER:` installation signature to
+   the installed launcher, then confirm the launcher starts GPTOKEYB with
+   `netfishing.gptk` and calls `pm_platform_helper` for the game executable.
 3. Confirm `conf/` and the external save directory were not replaced or
    removed.
 4. Launch the installed port through the normal muOS menu.
 5. Verify the displayed game version and controller face-button mapping.
-6. Verify PortMaster's force-quit chord exits the game. This is Start+Select on
-   most devices.
+6. Verify GPTOKEYB's device-specific force-quit chord exits the game. This is
+   Start+Select on most devices.
 
 Installing the public PortMaster catalog entry can still install an older
 catalog build until the upstream `netfishing.zip` is updated. A local release
@@ -173,12 +176,12 @@ the game process. This applies the mapping at the same point as the working
 reconstruction. Do not move the mapping back to either side of
 `westonwrap.sh`.
 
-Legacy GPTOKEYB builds can load their compiled default keyboard map when no
-`-c` file is supplied. That map translates face buttons, D-pad directions, and
-sticks into keyboard or mouse events on top of Godot's native controller input.
 Always pass `netfishing.gptk`, which explicitly unassigns every direct and
-hotkey binding with GPTOKEYB's `\"` value. Do not add gameplay mappings to this
-file. The Start+Select kill chord remains independent of the no-op bindings.
+hotkey binding with GPTOKEYB's `\"` value. This keeps GPTOKEYB from injecting
+keyboard or mouse events on top of Godot's native controller input and retains
+the device-specific kill chord. Supplying the explicit passthrough map also
+avoids the anomalous controller behavior observed on ROCKNIX when no map is
+provided. Do not add gameplay mappings to this file.
 
 Do not call `Input.add_joy_mapping(..., true)` for a recognized connected muOS
 controller. Updating this virtual controller after connection can stop Godot
diff --git a/scripts/build_portmaster.sh b/scripts/build_portmaster.sh
index b5ad5ae..833305b 100755
--- a/scripts/build_portmaster.sh
+++ b/scripts/build_portmaster.sh
@@ -223,7 +223,7 @@ music while omitting rain and shoreline ambience in both profiles. See
 
 ## Controls
 
-NETfishing reads the handheld controller directly. PortMaster's system
+NETfishing reads the handheld controller directly. GPTOKEYB's device-specific
 force-quit chord remains available; this is Start+Select on most devices.
 EOF
 
@@ -249,8 +249,11 @@ if unzip -Z1 "${ARCHIVE}" | grep -qx 'port.json'; then
   echo "port.json must be inside netfishing/, not at the archive root." >&2
   exit 1
 fi
-grep -q '^# PORTMASTER: netfishing.zip, NETfishing.sh$' \
-  "${STAGE_ROOT}/NETfishing.sh"
+if grep -Eq '^[[:space:]]*#[[:space:]]*PORTMASTER:' \
+  "${STAGE_ROOT}/NETfishing.sh"; then
+  echo "The distributable launcher contains an installed PortMaster signature." >&2
+  exit 1
+fi
 grep -Fq 'PROFILE_PATH="$CONFDIR/performance_profile"' \
   "${STAGE_ROOT}/NETfishing.sh"
 grep -Fq 'NETFISHING_PERFORMANCE_PROFILE=light' \
diff --git a/scripts/portmaster/NETfishing.sh b/scripts/portmaster/NETfishing.sh
index fe6d778..8e118da 100755
--- a/scripts/portmaster/NETfishing.sh
+++ b/scripts/portmaster/NETfishing.sh
@@ -1,5 +1,4 @@
 #!/bin/bash
-# PORTMASTER: netfishing.zip, NETfishing.sh
 
 XDG_DATA_HOME=${XDG_DATA_HOME:-$HOME/.local/share}
 
@@ -13,19 +12,11 @@ else
 	controlfolder="/roms/ports/PortMaster"
 fi
 
-if [ ! -f "$controlfolder/control.txt" ]; then
-	echo "PortMaster control.txt was not found at $controlfolder" >&2
-	exit 1
-fi
-
 source "$controlfolder/control.txt"
 [ -f "${controlfolder}/mod_${CFW_NAME}.txt" ] && source "${controlfolder}/mod_${CFW_NAME}.txt"
 get_controls
 
 GAMEDIR="/${directory}/ports/netfishing"
-if [ ! -d "$GAMEDIR" ] && [ -d "/mnt/mmc/ports/netfishing" ]; then
-	GAMEDIR="/mnt/mmc/ports/netfishing"
-fi
 
 CONFDIR="$GAMEDIR/conf"
 PORTS_ROOT="${GAMEDIR%/netfishing}"
@@ -38,16 +29,13 @@ CONTROLLER_MAPPING_FILE="$CONFDIR/cache/controller_mapping.txt"
 WESTON_DIR="/tmp/netfishing-weston"
 WESTON_RUNTIME="weston_pkg_0.2"
 HARBOURMASTER="$controlfolder/harbourmaster"
-if [ ! -x "$HARBOURMASTER" ] && [ -x "/mnt/mmc/MUOS/PortMaster/harbourmaster" ]; then
-	HARBOURMASTER="/mnt/mmc/MUOS/PortMaster/harbourmaster"
-fi
 
 mkdir -p "$CONFDIR/data" "$CONFDIR/config" "$CONFDIR/cache" "$WESTON_DIR"
 chmod +x "$GAME_EXECUTABLE"
 
-# New PortMaster installs use a predictable save directory beside the port
-# instead of presenting a folder picker on a small screen. Preserve an
-# established data-root choice when upgrading an existing installation.
+# NETfishing uses a predictable save directory beside the port instead of
+# presenting a folder picker on a small screen. Preserve an established
+# data-root choice when upgrading an existing installation.
 NETFISHING_DATA_ENVIRONMENT=()
 if [ -f "$SAVEDIR/netfishing_data.json" ] || {
 	[ ! -f "$DATA_BOOTSTRAP_DIR/data_root_bootstrap.json" ] &&
@@ -139,10 +127,9 @@ case "$PERFORMANCE_PROFILE" in
 		;;
 esac
 
-# Keep NETfishing's native controller input separate from PortMaster's exit
-# handling. Legacy GPTOKEYB builds can load their default keyboard map when no
-# config is supplied, so the explicit no-op map preserves only the
-# device-specific force-quit chord.
+# NETfishing reads gameplay input natively. The explicit no-op map prevents
+# GPTOKEYB from injecting duplicate keyboard or mouse input while retaining
+# its device-specific force-quit chord, including on ROCKNIX.
 $GPTOKEYB "NETfishing.aarch64" -c "$GPTOKEYB_CONFIG" &
 pm_platform_helper "$GAME_EXECUTABLE"
 
diff --git a/scripts/portmaster/netfishing.gptk b/scripts/portmaster/netfishing.gptk
index ac03270..ff1ad36 100644
--- a/scripts/portmaster/netfishing.gptk
+++ b/scripts/portmaster/netfishing.gptk
@@ -1,5 +1,6 @@
-# NETfishing reads the controller directly. GPTOKEYB is retained only for the
-# PortMaster force-quit chord, so every keyboard and mouse binding is disabled.
+# NETfishing reads the controller directly. GPTOKEYB is retained only for its
+# device-specific force-quit chord, so every keyboard and mouse binding is
+# disabled to prevent duplicate input.
 
 back = \"
 guide = \"