diff --git a/overlay/etc/skel/.reticulum/config.blueprint.mercury-only-node b/overlay/etc/skel/.reticulum/config.blueprint.mercury-only-node
index 1d2907c..0fb4276 100644
--- a/overlay/etc/skel/.reticulum/config.blueprint.mercury-only-node
+++ b/overlay/etc/skel/.reticulum/config.blueprint.mercury-only-node
@@ -93,5 +93,6 @@
 
     # Index  Mode     Payload Rate (bps)
     # 0      DATAC1   980
-    # 9      DATAC17  1410
+    # 9      DATAC17  1410 (not yet supported)
+    # 10     QAM16C2  3100 (not yet supported)
     bitrate = 980             
diff --git a/overlay/opt/emcomm-tools/bin/et-mercury b/overlay/opt/emcomm-tools/bin/et-mercury
index 54704f8..6b21dd6 100755
--- a/overlay/opt/emcomm-tools/bin/et-mercury
+++ b/overlay/opt/emcomm-tools/bin/et-mercury
@@ -16,6 +16,11 @@
 # keep usage simple, only three modulation settings have been configured
 # that map to a combination of reliability and speed for most general
 # purpose applications.
+#
+# The DATAC17 and QAM16C2 modes are documented on the RETICULUM.md
+# documenation on the mercury GitHub project, but are not yet supported
+# in version 1.9.9. Disabling these options from now.
+
 
 usage() {
   echo "usage: $(basename $0) <mode>"
@@ -39,9 +44,13 @@ case "${MODE}" in
   ;;
   balanced)
     MODE_INDEX="9"
+    et-log "Mode not yet supported."
+    exit 1
   ;;
   fast)
     MODE_INDEX="10"
+    et-log "Mode not yet supported."
+    exit 1
   ;;
   *)
     et-log "Can't started Mercury modem. Mode not supported."
diff --git a/overlay/opt/emcomm-tools/bin/et-reticulum b/overlay/opt/emcomm-tools/bin/et-reticulum
index 66ea060..ed1f4d3 100755
--- a/overlay/opt/emcomm-tools/bin/et-reticulum
+++ b/overlay/opt/emcomm-tools/bin/et-reticulum
@@ -111,8 +111,11 @@ if [[ $? -eq 0 ]]; then
   HAS_MERCURY_CONFIG=`grep "Mercury HF" ~/.reticulum/config`
   if [[ $? -eq 0 ]]; then
     modem_options+=("mercury-reliability" "Max reliability (Slower Speed) [DATAC1]")
-    modem_options+=("mercury-balanced" "Balanced (Reliability and Speed) [DATAC17]")
-    modem_options+=("mercury-fast" "Fast (Low Reliability) [QAM16C2]")
+    # The modes below, DATAC17 and QAM16C2, are documented on the RETICULUM.md
+    # documenation on the mercury GitHub project, but are not yet supported in
+    # version 1.9.9. Disabling these options from the UI for now.
+    #modem_options+=("mercury-balanced" "Balanced (Reliability and Speed) [DATAC17]")
+    #modem_options+=("mercury-fast" "Fast (Low Reliability) [QAM16C2]")
   fi
 
   modem_choice=$(dialog \