diff --git a/debian/changelog b/debian/changelog
index 3884069a2..ec4575ea0 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -18,6 +18,8 @@ linux (4.9-1~exp1) UNRELEASED; urgency=medium
   * [armhf] gpio: Enable GPIO_MCP23S08 as module (Closes: #845064)
   * aufs: Update support patchset to aufs4.9-20161219
   * Use debhelper compatibility level 9
+  * [arm64] Revert "arm64/mm: Limit TASK_SIZE_64 ..." and add breaks on
+    incompatible mozjs
 
   [ Uwe Kleine-König ]
   * enable `perf data' support; patch by Sebastian Andrzej Siewior
diff --git a/debian/config/arm64/defines b/debian/config/arm64/defines
index 6880132da..a50579a04 100644
--- a/debian/config/arm64/defines
+++ b/debian/config/arm64/defines
@@ -10,6 +10,7 @@ vdso: true
 
 [image]
 install-stem: vmlinuz
+breaks: libmozjs185-1.0, libmozjs-24-0 (<< 24.2.0-5.1~)
 
 [arm64_description]
 hardware: 64-bit ARMv8 machines
diff --git a/debian/patches/bugfix/arm64/arm64-mm-limit-task_size_64-for-compatibility.patch b/debian/patches/bugfix/arm64/arm64-mm-limit-task_size_64-for-compatibility.patch
deleted file mode 100644
index bc8423bec..000000000
--- a/debian/patches/bugfix/arm64/arm64-mm-limit-task_size_64-for-compatibility.patch
+++ /dev/null
@@ -1,27 +0,0 @@
-From: Ben Hutchings <ben@decadent.org.uk>
-Date: Fri, 16 Sep 2016 16:32:23 +0100
-Subject: arm64/mm: Limit TASK_SIZE_64 for compatibility
-
-Some programs assume they can use 17 tag bits in a 64-bit pointer,
-which works on most other 64-bit architectures but not on arm64 with
-CONFIG_ARM64_VA_BITS_48.  To maintain compatibility with these
-programs, limit TASK_SIZE_64 to a maximum of 1 << 47.
-
-Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
----
-
---- a/arch/arm64/include/asm/memory.h
-+++ b/arch/arm64/include/asm/memory.h
-@@ -74,7 +74,12 @@
- #define PCI_IO_END		(VMEMMAP_START - SZ_2M)
- #define PCI_IO_START		(PCI_IO_END - PCI_IO_SIZE)
- #define FIXADDR_TOP		(PCI_IO_START - SZ_2M)
-+#if VA_BITS <= 47
- #define TASK_SIZE_64		(UL(1) << VA_BITS)
-+#else
-+/* User-space might use up to 17 tag bits in 64-bit pointers */
-+#define TASK_SIZE_64		(UL(1) << 47)
-+#endif
- 
- #ifdef CONFIG_COMPAT
- #define TASK_SIZE_32		UL(0x100000000)
diff --git a/debian/patches/series b/debian/patches/series
index d528528e5..063e2986b 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -46,7 +46,6 @@ bugfix/x86/viafb-autoload-on-olpc-xo1.5-only.patch
 debian/fanotify-taint-on-use-of-fanotify_access_permissions.patch
 
 # Arch bug fixes
-bugfix/arm64/arm64-mm-limit-task_size_64-for-compatibility.patch
 bugfix/powerpc/powerpc-boot-request-no-dynamic-linker-for-boot-wrap.patch
 
 # Arch features