diff --git a/debian/changelog b/debian/changelog
index 0b92e1b2a..88bc1cb72 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+linux (4.9.10-2) UNRELEASED; urgency=medium
+
+  * [armel] dts: kirkwood: Fix SATA pinmux-ing for TS419 (Closes: #855017)
+
+ -- Ben Hutchings <ben@decadent.org.uk>  Sat, 18 Feb 2017 00:38:10 +0000
+
 linux (4.9.10-1) unstable; urgency=medium
 
   * New upstream stable update:
diff --git a/debian/patches/bugfix/arm/arm-dts-kirkwood-fix-sata-pinmux-ing-for-ts419.patch b/debian/patches/bugfix/arm/arm-dts-kirkwood-fix-sata-pinmux-ing-for-ts419.patch
new file mode 100644
index 000000000..9e6622fb0
--- /dev/null
+++ b/debian/patches/bugfix/arm/arm-dts-kirkwood-fix-sata-pinmux-ing-for-ts419.patch
@@ -0,0 +1,37 @@
+From: Ben Hutchings <ben@decadent.org.uk>
+Date: Fri, 17 Feb 2017 01:30:30 +0000
+Subject: ARM: dts: kirkwood: Fix SATA pinmux-ing for TS419
+Forwarded: https://www.spinics.net/lists/arm-kernel/msg563610.html
+Bug-Debian: https://bugs.debian.org/855017
+
+The old board code for the TS419 assigns MPP pins 15 and 16 as SATA
+activity signals (and none as SATA presence signals).  Currently the
+device tree assigns the SoC's default pinmux groups for SATA, which
+conflict with the second Ethernet port.
+
+Reported-by: gmbh@gazeta.pl
+Tested-by: gmbh@gazeta.pl
+References: https://bugs.debian.org/855017
+Cc: stable@vger.kernel.org # 3.15+
+Fixes: 934b524b3f49 ("ARM: Kirkwood: Add DT description of QNAP 419")
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+---
+ arch/arm/boot/dts/kirkwood-ts419.dtsi | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/arch/arm/boot/dts/kirkwood-ts419.dtsi b/arch/arm/boot/dts/kirkwood-ts419.dtsi
+index 02bd53762705..532506cb0f4a 100644
+--- a/arch/arm/boot/dts/kirkwood-ts419.dtsi
++++ b/arch/arm/boot/dts/kirkwood-ts419.dtsi
+@@ -73,3 +73,11 @@
+ 		phy-handle = <&ethphy1>;
+ 	};
+ };
++
++&pmx_sata0 {
++	marvell,pins = "mpp15";
++};
++
++&pmx_sata1 {
++	marvell,pins = "mpp16";
++};
diff --git a/debian/patches/series b/debian/patches/series
index 02e36647c..d5e6c2da9 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -50,6 +50,7 @@ debian/fanotify-taint-on-use-of-fanotify_access_permissions.patch
 bugfix/x86/asoc-intel-select-dw_dmac_core-since-it-s-mandatory.patch
 bugfix/x86/platform-x86-acer-wmi-setup-accelerometer-when-machi.patch
 bugfix/x86/x86-xen-fix-apic-id-mismatch-warning-on-intel.patch
+bugfix/arm/arm-dts-kirkwood-fix-sata-pinmux-ing-for-ts419.patch
 
 # Arch features
 features/mips/MIPS-increase-MAX-PHYSMEM-BITS-on-Loongson-3-only.patch