diff --git a/srcpkgs/mozjs78/patches/build-non-jit-32bit.patch b/srcpkgs/mozjs78/patches/build-non-jit-32bit.patch
new file mode 100644
index 00000000000..e3938fe8780
--- /dev/null
+++ b/srcpkgs/mozjs78/patches/build-non-jit-32bit.patch
@@ -0,0 +1,14 @@
+On 32-bit systems without JIT, the GC doesn't like 4-byte alignment,
+so enforce a stricter one.
+
+--- js/src/jit/none/MacroAssembler-none.h.orig	2021-04-12 00:05:00.691183973 +0200
++++ js/src/jit/none/MacroAssembler-none.h	2021-04-12 00:05:10.336183909 +0200
+@@ -100,7 +100,7 @@ static constexpr Register WasmTlsReg{Reg
+ static constexpr Register WasmJitEntryReturnScratch{Registers::invalid_reg};
+ 
+ static constexpr uint32_t ABIStackAlignment = 4;
+-static constexpr uint32_t CodeAlignment = 16;
++static constexpr uint32_t CodeAlignment = 8;
+ static constexpr uint32_t JitStackAlignment = 8;
+ static constexpr uint32_t JitStackValueAlignment =
+     JitStackAlignment / sizeof(Value);
diff --git a/srcpkgs/mozjs78/template b/srcpkgs/mozjs78/template
index 7b437946b19..ee443e7a64c 100644
--- a/srcpkgs/mozjs78/template
+++ b/srcpkgs/mozjs78/template
@@ -1,7 +1,7 @@
 # Template file for 'mozjs78'
 pkgname=mozjs78
 version=78.9.0
-revision=1
+revision=2
 wrksrc="firefox-${version}"
 build_wrksrc=js/src
 build_style=gnu-configure