diff --git a/net/modemmanager/Makefile b/net/modemmanager/Makefile
index f327b1486..779757817 100644
--- a/net/modemmanager/Makefile
+++ b/net/modemmanager/Makefile
@@ -92,6 +92,7 @@ define Package/modemmanager/install
 	$(INSTALL_DIR) $(1)/usr/sbin
 	$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/sbin/ModemManager $(1)/usr/sbin
 	$(INSTALL_BIN) ./files/usr/sbin/ModemManager-wrapper $(1)/usr/sbin
+	$(INSTALL_BIN) ./files/usr/sbin/ModemManager-monitor $(1)/usr/sbin
 
 	$(INSTALL_DIR) $(1)/usr/bin
 	$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/bin/mmcli $(1)/usr/bin
@@ -118,9 +119,6 @@ define Package/modemmanager/install
 	$(INSTALL_DIR) $(1)/etc/init.d
 	$(INSTALL_BIN) ./files/modemmanager.init $(1)/etc/init.d/modemmanager
 
-	$(INSTALL_DIR) $(1)/etc/hotplug.d/usb
-	$(INSTALL_DATA) ./files/25-modemmanager-usb $(1)/etc/hotplug.d/usb
-
 	$(INSTALL_DIR) $(1)/etc/hotplug.d/net
 	$(INSTALL_DATA) ./files/25-modemmanager-net $(1)/etc/hotplug.d/net
 
diff --git a/net/modemmanager/files/25-modemmanager-usb b/net/modemmanager/files/25-modemmanager-usb
deleted file mode 100644
index 93d0bf70a..000000000
--- a/net/modemmanager/files/25-modemmanager-usb
+++ /dev/null
@@ -1,13 +0,0 @@
-#!/bin/sh
-# Copyright (C) 2019 Aleksander Morgado <aleksander@aleksander.es>
-
-# We need to process only full USB device removal events, we don't
-# want to process specific interface removal events.
-[ "$ACTION" = remove ] || exit
-[ -z "${INTERFACE}" ] || exit
-
-# Load common utilities
-. /usr/share/ModemManager/modemmanager.common
-
-mm_clear_modem_wait_status "/sys${DEVPATH}"
-mm_cleanup_interface_by_sysfspath "/sys${DEVPATH}"
diff --git a/net/modemmanager/files/modemmanager.common b/net/modemmanager/files/modemmanager.common
index 4daffb2c1..b3f86db9a 100644
--- a/net/modemmanager/files/modemmanager.common
+++ b/net/modemmanager/files/modemmanager.common
@@ -13,7 +13,7 @@
 MODEMMANAGER_RUNDIR="/var/run/modemmanager"
 MODEMMANAGER_PID_FILE="${MODEMMANAGER_RUNDIR}/modemmanager.pid"
 MODEMMANAGER_CDCWDM_CACHE="${MODEMMANAGER_RUNDIR}/cdcwdm.cache"
-MODEMMANAGER_SYSFS_CACHE="${MODEMMANAGER_RUNDIR}/sysfs.cache"
+MODEMMANAGER_MONITOR_CACHE="${MODEMMANAGER_RUNDIR}/monitor.cache"
 MODEMMANAGER_EVENTS_CACHE="${MODEMMANAGER_RUNDIR}/events.cache"
 
 ################################################################################
@@ -92,48 +92,6 @@ mm_untrack_cdcwdm() {
 	echo "${cdcwdm}"
 }
 
-################################################################################
-# ModemManager needs some time from the ports being added until a modem object
-# is exposed in DBus. With the logic here we do an explicit wait of N seconds
-# for ModemManager to expose the new modem object, making sure that the wait is
-# unique per device (i.e. per physical device sysfs path).
-
-# Gets the modem wait status as retrieved from the cache
-mm_get_modem_wait_status() {
-	local sysfspath="$1"
-
-	# If no sysfs cache file, we're done
-	[ -f "${MODEMMANAGER_SYSFS_CACHE}" ] || return
-
-	# Get status of the sysfs path
-	awk -v sysfspath="${sysfspath}" '!/^#/ && $0 ~ sysfspath { print $2 }' "${MODEMMANAGER_SYSFS_CACHE}"
-}
-
-# Clear the modem wait status from the cache, if any
-mm_clear_modem_wait_status() {
-	local sysfspath="$1"
-
-	local escaped_sysfspath
-
-	[ -f "${MODEMMANAGER_SYSFS_CACHE}" ] && {
-		# escape '/', '\' and '&' for sed...
-		escaped_sysfspath=$(echo "$sysfspath" | sed -e 's/[\/&]/\\&/g')
-		sed -i "/${escaped_sysfspath}/d" "${MODEMMANAGER_SYSFS_CACHE}"
-	}
-}
-
-# Sets the modem wait status in the cache
-mm_set_modem_wait_status() {
-	local sysfspath="$1"
-	local status="$2"
-
-	# Remove sysfs line before adding the new one with the new state
-	mm_clear_modem_wait_status "${sysfspath}"
-
-	# Add the new status
-	echo "${sysfspath} ${status}" >> "${MODEMMANAGER_SYSFS_CACHE}"
-}
-
 # Callback for config_foreach()
 mm_get_modem_config_foreach_cb() {
 	local cfg="$1"
@@ -155,112 +113,6 @@ mm_get_modem_config() {
 	config_foreach mm_get_modem_config_foreach_cb interface "${sysfspath}"
 }
 
-# Wait for a modem in the specified sysfspath
-mm_wait_for_modem() {
-	local cfg="$1"
-	local sysfspath="$2"
-
-	# TODO: config max wait
-	local n=45
-	local step=5
-
-	while [ $n -ge 0 ]; do
-		[ -d "${sysfspath}" ] || {
-			mm_log "error" "ignoring modem detection request: no device at ${sysfspath}"
-			proto_set_available "${cfg}" 0
-			return 1
-		}
-
-		# Check if the modem exists at the given sysfs path
-		if ! mmcli -m "${sysfspath}" > /dev/null 2>&1
-		then
-			mm_log "error" "modem not detected at sysfs path"
-		else
-			mm_log "info" "modem exported successfully at ${sysfspath}"
-			mm_log "info" "setting interface '${cfg}' as available"
-			proto_set_available "${cfg}" 1
-			return 0
-		fi
-
-		sleep $step
-		n=$((n-step))
-	done
-
-	mm_log "error" "timed out waiting for the modem to get exported at ${sysfspath}"
-	proto_set_available "${cfg}" 0
-	return 2
-}
-
-mm_report_modem_wait() {
-	local sysfspath=$1
-
-	local parent_sysfspath status
-
-	parent_sysfspath=$(mm_find_physdev_sysfs_path "$sysfspath")
-	[ -n "${parent_sysfspath}" ] || {
-		mm_log "error" "parent device sysfspath not found"
-		return
-	}
-
-	status=$(mm_get_modem_wait_status "${parent_sysfspath}")
-	case "${status}" in
-		"")
-			local cfg
-
-			cfg=$(mm_get_modem_config "${parent_sysfspath}")
-			if [ -n "${cfg}" ]; then
-				mm_log "info" "interface '${cfg}' is set to configure device '${parent_sysfspath}'"
-				mm_log "info" "now waiting for modem at sysfs path ${parent_sysfspath}"
-				mm_set_modem_wait_status "${parent_sysfspath}" "processed"
-				# Launch subshell for the explicit wait
-				( mm_wait_for_modem "${cfg}" "${parent_sysfspath}" ) > /dev/null 2>&1 &
-			else
-				mm_log "info" "no need to wait for modem at sysfs path ${parent_sysfspath}"
-				mm_set_modem_wait_status "${parent_sysfspath}" "ignored"
-			fi
-			;;
-		"processed")
-			mm_log "info" "already waiting for modem at sysfs path ${parent_sysfspath}"
-			;;
-		"ignored")
-			;;
-		*)
-			mm_log "error" "unknown status read for device at sysfs path ${parent_sysfspath}"
-			;;
-	esac
-}
-
-################################################################################
-# Cleanup interfaces
-
-mm_cleanup_interfaces() {
-	local sysfs_path status
-
-	# Do nothing if there is no sysfs cache
-	[ -f "${MODEMMANAGER_SYSFS_CACHE}" ] || return
-
-	while IFS= read -r sysfs_cache_line; do
-		sysfs_path=$(echo "${sysfs_cache_line}" | awk '{print $1}')
-		status=$(echo "${sysfs_cache_line}" | awk '{print $2}')
-
-		if [ "${status}" = "processed" ]; then
-			mm_log "debug" "call cleanup for: ${sysfs_path}"
-			mm_cleanup_interface_by_sysfspath "${sysfs_path}"
-		fi
-	done < ${MODEMMANAGER_SYSFS_CACHE}
-}
-
-mm_cleanup_interface_by_sysfspath() {
-	local dev="$1"
-
-	local cfg
-	cfg=$(mm_get_modem_config "$dev")
-	[ -n "${cfg}" ] || return
-
-	mm_log "info" "setting interface '$cfg' as unavailable"
-	proto_set_available "${cfg}" 0
-}
-
 ################################################################################
 # Event reporting
 
@@ -295,13 +147,9 @@ mm_report_event() {
 	# Report the event
 	mm_log "debug" "Report event: action=${action}, name=${name}, subsystem=${subsystem}"
 	result=$(mmcli --report-kernel-event="action=${action},name=${name},subsystem=${subsystem}" 2>&1)
-	if [ "$?" -eq "0" ]; then
-		# Wait for added modem if a sysfspath is given
-		[ -n "${sysfspath}" ] && [ "$action" = "add" ] && mm_report_modem_wait "${sysfspath}"
-	else
+	if [ "$?" -ne "0" ]; then
 		mm_log "error" "Couldn't report kernel event: ${result}"
 	fi
-
 }
 
 mm_report_event_from_cache_line() {
diff --git a/net/modemmanager/files/modemmanager.init b/net/modemmanager/files/modemmanager.init
index a036d884d..ccc1953ae 100755
--- a/net/modemmanager/files/modemmanager.init
+++ b/net/modemmanager/files/modemmanager.init
@@ -21,11 +21,15 @@ start_service() {
 	# wrapper script called '/usr/sbin/ModemManager-wrapper'.
 	#
 	. /usr/share/ModemManager/modemmanager.common
-	procd_open_instance
+	procd_open_instance "service"
 	procd_set_param command /usr/sbin/ModemManager-wrapper
 	procd_append_param command --log-level="$LOG_LEVEL"
 	[ "$LOG_LEVEL" = "DEBUG" ] && procd_append_param command --debug
 	procd_set_param respawn "${respawn_threshold:-3600}" "${respawn_timeout:-5}" "${respawn_retry:-5}"
 	procd_set_param pidfile "${MODEMMANAGER_PID_FILE}"
 	procd_close_instance
+	procd_open_instance "monitor"
+	procd_set_param command /usr/sbin/ModemManager-monitor
+	procd_set_param respawn "${respawn_threshold:-3600}" "${respawn_timeout:-5}" "${respawn_retry:-5}"
+	procd_close_instance
 }
diff --git a/net/modemmanager/files/usr/sbin/ModemManager-monitor b/net/modemmanager/files/usr/sbin/ModemManager-monitor
new file mode 100644
index 000000000..8a88ab514
--- /dev/null
+++ b/net/modemmanager/files/usr/sbin/ModemManager-monitor
@@ -0,0 +1,155 @@
+#!/bin/sh
+
+. /lib/functions.sh
+. /lib/netifd/netifd-proto.sh
+. /usr/share/ModemManager/modemmanager.common
+
+trap_with_arg() {
+	func="$1" ; shift
+	for sig ; do
+		# shellcheck disable=SC2064
+		trap "$func $sig" "$sig"
+	done
+}
+
+func_trap() {
+	local monitor_cache_line object
+
+	logger "ModemManager-monitor[$$]" "Sending signal ${1} ..."
+
+	# Set all configured logical interfaces to unavailable
+	while IFS= read -r monitor_cache_line; do
+		object=$(echo "${monitor_cache_line}" | awk '{print $1}')
+		mm_monitor_cache_remove "$object"
+	done < ${MODEMMANAGER_MONITOR_CACHE}
+
+	kill "-${1}" "$CHILD" 2>/dev/null
+}
+
+mm_monitor_get_sysfspath() {
+	local object="$1"
+
+	# If no monitor cache file, we're done
+	[ -f "${MODEMMANAGER_MONITOR_CACHE}" ] || return
+
+	awk -v object="${object}" '!/^#/ && $0 ~ object { print $2 }' "${MODEMMANAGER_MONITOR_CACHE}"
+}
+
+mm_monitor_cache_remove() {
+	local object="$1"
+
+	local device cfg
+
+	device=$(mm_monitor_get_sysfspath "${object}")
+
+	cfg=$(mm_get_modem_config "${device}")
+	if [ -n "${cfg}" ]; then
+		mm_log "debug" "interface '${cfg}' set '${device}' state unavailable"
+		proto_set_available "${cfg}" 0
+	fi
+
+	mm_log "debug" "delete object '$object' from monitore cache"
+
+	# On monitor remove event, remove old events from cache
+	# Also substitute object path '/org/freedesktop/ModemManager1/Modem/<number>'
+	# all '/' with '\/' to make sed happy with shell expansion
+	sed -i "/${object//\//\\/}/d" "${MODEMMANAGER_MONITOR_CACHE}"
+}
+
+mm_monitor_cache_add() {
+	local object="$1"
+	local modemstatus device sysfspath cfg
+
+	modemstatus="$(mmcli --modem="${object}" --output-keyvalue)"
+
+	device=$(modemmanager_get_field "${modemstatus}" "modem.generic.device")
+	[ -n "${device}" ] || {
+		mm_log "err" "No 'device' for object '$object' not found..."
+		return 1
+	}
+
+	sysfspath=$(modemmanager_get_field "${modemstatus}" "modem.generic.physdev")
+	[ -n "${sysfspath}" ] || {
+		mm_log "err" "No 'sysfspath' for object '$object' not found..."
+		return 2
+	}
+
+	mm_log "debug" "add object '$object' to monitore cache (device=${device},sysfspath=${sysfspath})"
+
+	# On monitor add event, store event details in cache (if not exists yet)
+	grep -qs "${sysfspath}" "${MODEMMANAGER_MONITOR_CACHE}" || \
+		echo "${object} ${device} ${sysfspath}" >> "${MODEMMANAGER_MONITOR_CACHE}"
+
+	cfg=$(mm_get_modem_config "${device}")
+	if [ -n "${cfg}" ]; then
+		mm_log "info" "interface '${cfg}' set '${device}' state available"
+		proto_set_available "${cfg}" 1
+	fi
+}
+
+mm_monitor_cache_del() {
+	local object="$1"
+
+	mm_monitor_cache_remove "$object"
+}
+
+mm_monitor_cache() {
+	local line="$1"
+	local event object modemstatus device pyhsdev
+
+	event="$(echo "$line" | cut -d " " -f 1)"
+	object="$(echo "$line" | cut -d " " -f 2)"
+
+	case "$event" in
+		"(+)")
+			mm_monitor_cache_add "$object"
+			;;
+		"(-)")
+			mm_monitor_cache_del "$object"
+			;;
+	esac
+}
+
+main() {
+
+	local n=60
+	local step=1
+	local mmrunning=0
+
+	trap_with_arg func_trap INT TERM KILL
+
+	mkdir -p "${MODEMMANAGER_RUNDIR}"
+	chmod 0755 "${MODEMMANAGER_RUNDIR}"
+
+	# Wait for ModemManager to be available in the bus
+	while [ $n -ge 0 ]; do
+		sleep $step
+		mm_log "info" "Checking if ModemManager is available..."
+
+		if ! /usr/bin/mmcli -L >/dev/null 2>&1; then
+			mm_log "info" "ModemManager not yet available"
+		else
+			mmrunning=1
+			break
+		fi
+		n=$((n-step))
+	done
+
+	[ ${mmrunning} -eq 1 ] || {
+		mm_log "error" "couldn't report initial kernel events: ModemManager not running"
+		return
+	}
+
+	/usr/bin/mmcli -M | {
+		local line
+		while read -r line; do
+			mm_log "debug" "Monitor cache line: ${line}"
+			mm_monitor_cache "$line"
+		done
+	} &
+	CHILD="$!"
+
+	wait $CHILD
+}
+
+main "$@"
diff --git a/net/modemmanager/files/usr/sbin/ModemManager-wrapper b/net/modemmanager/files/usr/sbin/ModemManager-wrapper
index 5ca530b16..b0f36c267 100644
--- a/net/modemmanager/files/usr/sbin/ModemManager-wrapper
+++ b/net/modemmanager/files/usr/sbin/ModemManager-wrapper
@@ -27,9 +27,6 @@ main() {
 	mm_report_events_from_cache
 
 	wait "$CHILD"
-
-	# Set all configured interfaces as unavailable
-	mm_cleanup_interfaces
 }
 
 main "$@"