diff --git a/src/arith_uint256.cpp b/src/arith_uint256.cpp
--- a/src/arith_uint256.cpp
+++ b/src/arith_uint256.cpp
@@ -104,7 +104,7 @@
         if (num >= div) {
             num -= div;
             // set a bit of the result.
-            pn[shift / 32] |= (1 << (shift & 31));
+            pn[shift / 32] |= (1U << (shift & 31));
         }
         // shift back.
         div >>= 1;
@@ -239,7 +239,7 @@
         nCompact >>= 8;
         nSize++;
     }
-    assert((nCompact & ~0x007fffff) == 0);
+    assert((nCompact & ~0x007fffffU) == 0);
     assert(nSize < 256);
     nCompact |= nSize << 24;
     nCompact |= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0);
diff --git a/test/sanitizer_suppressions/ubsan b/test/sanitizer_suppressions/ubsan
--- a/test/sanitizer_suppressions/ubsan
+++ b/test/sanitizer_suppressions/ubsan
@@ -39,7 +39,6 @@
 implicit-integer-sign-change:*/include/c++/*/bits/*.h
 implicit-integer-sign-change:*/new_allocator.h
 implicit-integer-sign-change:/usr/include/boost/date_time/format_date_parser.hpp
-implicit-integer-sign-change:arith_uint256.cpp
 implicit-integer-sign-change:bech32.cpp
 implicit-integer-sign-change:bloom.cpp
 implicit-integer-sign-change:chain.*