diff -Nru pi-bluetooth-0.1.15ubuntu1/debian/changelog pi-bluetooth-0.1.15ubuntu1~20.10.1/debian/changelog
--- pi-bluetooth-0.1.15ubuntu1/debian/changelog	2020-10-14 19:29:19.000000000 -0500
+++ pi-bluetooth-0.1.15ubuntu1~20.10.1/debian/changelog	2021-04-26 09:40:19.000000000 -0500
@@ -1,3 +1,7 @@
+pi-bluetooth (0.1.15ubuntu1~20.10.1) groovy; urgency=medium
+
+  * Merged upstream fixes for CM4 and Pi 400 (LP: #1921915)
+
 pi-bluetooth (0.1.15ubuntu1) groovy; urgency=medium
 
   * Merged new upstream version (LP: #1897920)
diff -Nru pi-bluetooth-0.1.15ubuntu1/debian/pi-bluetooth.bthelper@.service pi-bluetooth-0.1.15ubuntu1~20.10.1/debian/pi-bluetooth.bthelper@.service
--- pi-bluetooth-0.1.15ubuntu1/debian/pi-bluetooth.bthelper@.service	2018-08-20 11:01:22.000000000 -0500
+++ pi-bluetooth-0.1.15ubuntu1~20.10.1/debian/pi-bluetooth.bthelper@.service	2021-03-30 09:34:52.000000000 -0500
@@ -4,5 +4,6 @@
 After=bluetooth.service
 
 [Service]
-Type=simple
+Type=oneshot
 ExecStart=/usr/bin/bthelper %I
+RemainAfterExit=yes
diff -Nru pi-bluetooth-0.1.15ubuntu1/usr/bin/bthelper pi-bluetooth-0.1.15ubuntu1~20.10.1/usr/bin/bthelper
--- pi-bluetooth-0.1.15ubuntu1/usr/bin/bthelper	2020-08-19 09:33:51.000000000 -0500
+++ pi-bluetooth-0.1.15ubuntu1~20.10.1/usr/bin/bthelper	2021-03-30 09:34:52.000000000 -0500
@@ -18,9 +18,7 @@
     exit 0
 fi
 
-if ( /usr/bin/hcitool -i $dev dev | grep -q -E '\s(B8:27:EB:|DC:A6:32:)' ); then
-    echo Raspberry Pi BDADDR already set
-else
+if ( /usr/bin/hcitool -i $dev dev | grep -q -E '\s43:4[35]:' ); then
     SERIAL=`cat /proc/device-tree/serial-number | cut -c9-`
     B1=`echo $SERIAL | cut -c3-4`
     B2=`echo $SERIAL | cut -c5-6`
@@ -29,6 +27,8 @@
 
     /usr/bin/hcitool -i $dev cmd 0x3f 0x001 $BDADDR
     /bin/hciconfig $dev reset
+else
+    echo Raspberry Pi BDADDR already set
 fi
 
 # Force reinitialisation to allow extra features such as Secure Simple Pairing
diff -Nru pi-bluetooth-0.1.15ubuntu1/usr/bin/btuart pi-bluetooth-0.1.15ubuntu1~20.10.1/usr/bin/btuart
--- pi-bluetooth-0.1.15ubuntu1/usr/bin/btuart	2020-07-29 02:42:59.000000000 -0500
+++ pi-bluetooth-0.1.15ubuntu1~20.10.1/usr/bin/btuart	2021-03-30 09:34:52.000000000 -0500
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 HCIATTACH=/usr/bin/hciattach
-if grep -q "Pi 4" /proc/device-tree/model; then
+if grep -q "raspberrypi,4" /proc/device-tree/compatible; then
   BDADDR=
 else
   SERIAL=`cat /proc/device-tree/serial-number | cut -c9-`
@@ -11,8 +11,8 @@
   BDADDR=`printf b8:27:eb:%02x:%02x:%02x $((0x$B1 ^ 0xaa)) $((0x$B2 ^ 0xaa)) $((0x$B3 ^ 0xaa))`
 fi
 
-if [ -e /sys/class/bluetooth/hci0 ]; then
-  # Bluetooth is already enabled
+if ( /usr/bin/hcitool dev | grep -q -E '\s(B8:27:EB:|DC:A6:32:)' ); then
+  # On-board bluetooth is already enabled
   exit 0
 fi