diff --git a/mfbt/double-conversion/double-conversion.cc b/mfbt/double-conversion/double-conversion.cc
index 650137b492d0..a79fe92d2255 100644
--- a/mfbt/double-conversion/double-conversion.cc
+++ b/mfbt/double-conversion/double-conversion.cc
@@ -162,7 +162,7 @@ bool DoubleToStringConverter::ToShortestIeeeNumber(
     double value,
     StringBuilder* result_builder,
     DoubleToStringConverter::DtoaMode mode) const {
-  assert(mode == SHORTEST || mode == SHORTEST_SINGLE);
+  ASSERT(mode == SHORTEST || mode == SHORTEST_SINGLE);
   if (Double(value).IsSpecial()) {
     return HandleSpecialValues(value, result_builder);
   }
diff --git a/mfbt/double-conversion/fast-dtoa.cc b/mfbt/double-conversion/fast-dtoa.cc
index 0609422798a9..1a0f8235092f 100644
--- a/mfbt/double-conversion/fast-dtoa.cc
+++ b/mfbt/double-conversion/fast-dtoa.cc
@@ -529,7 +529,7 @@ static bool Grisu3(double v,
   if (mode == FAST_DTOA_SHORTEST) {
     Double(v).NormalizedBoundaries(&boundary_minus, &boundary_plus);
   } else {
-    assert(mode == FAST_DTOA_SHORTEST_SINGLE);
+    ASSERT(mode == FAST_DTOA_SHORTEST_SINGLE);
     float single_v = static_cast<float>(v);
     Single(single_v).NormalizedBoundaries(&boundary_minus, &boundary_plus);
   }
diff --git a/mfbt/double-conversion/more-architectures.patch b/mfbt/double-conversion/more-architectures.patch
deleted file mode 100644
index b8d38047e36f..000000000000
--- a/mfbt/double-conversion/more-architectures.patch
+++ /dev/null
@@ -1,30 +0,0 @@
-diff --git a/mfbt/double-conversion/utils.h b/mfbt/double-conversion/utils.h
---- a/mfbt/double-conversion/utils.h
-+++ b/mfbt/double-conversion/utils.h
-@@ -48,20 +48,24 @@
- // An easy way to test if the floating-point operations are correct is to
- // evaluate: 89255.0/1e22. If the floating-point stack is 64 bits wide then
- // the result is equal to 89255e-22.
- // The best way to test this, is to create a division-function and to compare
- // the output of the division with the expected result. (Inlining must be
- // disabled.)
- // On Linux,x86 89255e-22 != Div_double(89255.0/1e22)
- #if defined(_M_X64) || defined(__x86_64__) || \
--    defined(__ARMEL__) || \
-+    defined(__ARMEL__) || defined(__avr32__) || \
-+    defined(__hppa__) || defined(__ia64__) || \
-+    defined(__mips__) || defined(__powerpc__) || \
-+    defined(__sparc__) || defined(__sparc) || defined(__s390__) || \
-+    defined(__SH4__) || defined(__alpha__) || \
-     defined(_MIPS_ARCH_MIPS32R2)
- #define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
--#elif defined(_M_IX86) || defined(__i386__)
-+#elif defined(_M_IX86) || defined(__i386__) || defined(__i386)
- #if defined(_WIN32)
- // Windows uses a 64bit wide floating point stack.
- #define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
- #else
- #undef DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS
- #endif  // _WIN32
- #else
- #error Target architecture was not detected as supported by Double-Conversion.
diff --git a/mfbt/double-conversion/strtod.cc b/mfbt/double-conversion/strtod.cc
index d5abc937c9df..9758989f71db 100644
--- a/mfbt/double-conversion/strtod.cc
+++ b/mfbt/double-conversion/strtod.cc
@@ -515,15 +515,15 @@ float Strtof(Vector<const char> buffer, int exponent) {
     double double_next2 = Double(double_next).NextDouble();
     f4 = static_cast<float>(double_next2);
   }
-  assert(f1 <= f2 && f2 <= f3 && f3 <= f4);
+  ASSERT(f1 <= f2 && f2 <= f3 && f3 <= f4);
 
   // If the guess doesn't lie near a single-precision boundary we can simply
   // return its float-value.
-  if ((f1 == f4)) {
+  if (f1 == f4) {
     return float_guess;
   }
 
-  assert((f1 != f2 && f2 == f3 && f3 == f4) ||
+  ASSERT((f1 != f2 && f2 == f3 && f3 == f4) ||
          (f1 == f2 && f2 != f3 && f3 == f4) ||
          (f1 == f2 && f2 == f3 && f3 != f4));
 
diff --git a/mfbt/double-conversion/update.sh b/mfbt/double-conversion/update.sh
index 81add8ef7c05..43091e31253c 100755
--- a/mfbt/double-conversion/update.sh
+++ b/mfbt/double-conversion/update.sh
@@ -3,6 +3,10 @@
 # Copies the needed files from a directory containing the original
 # double-conversion source that we need.
 
+# This was last updated with git rev e5b34421b763f7bf7e4f9081403db417d5a55a36.
+
+set -e
+
 cp $1/LICENSE ./
 cp $1/README ./
 
@@ -14,4 +18,3 @@ cp $1/src/*.cc ./
 
 patch -p3 < add-mfbt-api-markers.patch
 patch -p3 < use-StandardInteger.patch
-patch -p3 < more-architectures.patch