diff --git a/Makefile b/Makefile
index 41dee7e..acfd0dc 100644
--- a/Makefile
+++ b/Makefile
@@ -54,12 +54,12 @@ install: $(PROGRAMS) help2man
 	mkdir -p $(DESTDIR)$(prefix)$(htdocs)/galmon
 	cp -a html $(DESTDIR)$(prefix)$(htdocs)/galmon/
 
-install-debian:
+download-debian-package:
 	apt-key adv --fetch-keys https://ota.bike/public-package-signing-keys/86E7F51C04FBAAB0.asc
 	echo "deb https://ota.bike/debian/ buster main" > /etc/apt/sources.list.d/galmon.list
 	apt-get update && apt-get install -y galmon
 
-install-raspbian:
+download-raspbian-package:
 	apt-key adv --fetch-keys https://ota.bike/public-package-signing-keys/86E7F51C04FBAAB0.asc
 	echo "deb https://ota.bike/raspbian/ buster main" > /etc/apt/sources.list.d/galmon.list
 	apt-get update && apt-get install -y galmon
diff --git a/PACKAGE-DEBIAN.md b/PACKAGE-DEBIAN.md
index 3b8ae0f..2239fcd 100644
--- a/PACKAGE-DEBIAN.md
+++ b/PACKAGE-DEBIAN.md
@@ -20,17 +20,20 @@ apt-key adv --fetch-keys https://ota.bike/public-package-signing-keys/86E7F51C04
 ```
 
 Update your package list and install galmon. Then create a configuration file and start the daemon.
+If you have a typical device using the onboard USB at /dev/ttyACM0, drop the directory element
+and refer to ttyACM0 in both the default variable file and the unit name.
 ```sh
 apt-get update && apt-get install -y galmon
 cp /etc/default/galmon /etc/default/ubxtool-ttyACM0
 systemctl enable --now ubxtool@ttyACM0
 ```
 
-Alternate or multiple devices just repeats that:
+Alternate or multiple devices just repeats that, updating the device name:
 ```sh
 cp /etc/default/galmon /etc/default/ubxtool-ttyACM3
 systemctl enable --now ubxtool@ttyACM3
 ```
+Both the ubxtool-ttyXYZn file and /dev/ttyXYZn device must exist for the unit file conditions to pass.
 
 ### Automatic Updates
 
@@ -44,7 +47,7 @@ systemctl enable --now galmon-upgrade.timer
 
 You can perform an immediate update by hand:
 ```sh
-apt-get update && apt-get -y upgrade galmon && systemctl restart ubxtool@*
+apt-get update && apt-get -y install galmon && systemctl restart ubxtool@*
 ```
 
 ## Reference Information
diff --git a/debian/galmon.default b/debian/galmon.default
index 204d226..82ae9b1 100644
--- a/debian/galmon.default
+++ b/debian/galmon.default
@@ -3,13 +3,14 @@
 # This package is free software: /usr/share/common-licenses/GPL-3
 #
 # INSTRUCTIONS:
+#   (Pre-condition: "dmesg | tail" reports your GPS device appears on /dev/ttyACM0.)
 #   Copy this file from /etc/default/galmon to /etc/default/ubxtool-ttyACM0
 #   Please choose your constellations, update the owner and remark, and set your station and destination (ipv6 supported)
 #   After customization, start the daemon: 
 #     systemctl enable --now ubxtool@ttyACM0 && journalctl -fu ubxtool
 #   If you want, enable automatic upgrades at boot and every three days following:
 #     systemctl enable --now galmon-upgrade.timer
-# 
+#   If you have several devices, enable multiple services with their unique device names.
 #
 # FOR HELP:
 #   Review the Operator.md file: https://github.com/ahupowerdns/galmon/blob/master/Operator.md