diff --git a/src/bitboard.h b/src/bitboard.h
index c3130b4c..3476924c 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -63,7 +63,9 @@ extern Bitboard StarSquareBB12;
 
 inline Bitboard square_bb(Square s)
 {
-    assert(SQ_BEGIN <= s && s < SQ_END);
+    if (!(SQ_BEGIN <= s && s < SQ_END))
+        return 0;
+
     return SquareBB[s];
 }
 
diff --git a/src/misc.cpp b/src/misc.cpp
index 88256411..df9f1f4f 100644
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -545,6 +545,8 @@ int best_group(size_t idx)
 
     // Early exit if the needed API is not available at runtime
     HMODULE k32 = GetModuleHandle(L"Kernel32.dll");
+    if (k32 == nullptr)
+        return -1;
     auto fun1 = (fun1_t)(void(*)())GetProcAddress(k32, "GetLogicalProcessorInformationEx");
     if (!fun1)
         return -1;
@@ -557,6 +559,9 @@ int best_group(size_t idx)
     SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *buffer, *ptr;
     ptr = buffer = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *)malloc(returnLength);
 
+    if (ptr == nullptr)
+        return -1;
+
     // Second call, now we expect to succeed
     if (!fun1(RelationAll, buffer, &returnLength)) {
         free(buffer);
@@ -611,6 +616,8 @@ void bindThisThread(size_t idx)
 
     // Early exit if the needed API are not available at runtime
     HMODULE k32 = GetModuleHandle(L"Kernel32.dll");
+    if (k32 == nullptr)
+        return;
     auto fun2 = (fun2_t)(void(*)())GetProcAddress(k32, "GetNumaNodeProcessorMaskEx");
     auto fun3 = (fun3_t)(void(*)())GetProcAddress(k32, "SetThreadGroupAffinity");
 
diff --git a/src/position.cpp b/src/position.cpp
index e901035a..094987cc 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1083,7 +1083,7 @@ int Position::potential_mills_count(Square to, Color c, Square from)
         c = color_on(to);
     }
 
-    if (from != SQ_0) {
+    if (from != SQ_0 && from >= SQ_BEGIN && from < SQ_END) {
         locbak = board[from];
         board[from] = NO_PIECE;
 
@@ -1101,7 +1101,7 @@ int Position::potential_mills_count(Square to, Color c, Square from)
         }
     }
 
-    if (from != SQ_0) {
+    if (from != SQ_0 && from >= SQ_BEGIN && from < SQ_END) {
         board[from] = locbak;
 
         SET_BIT(byTypeBB[ALL_PIECES], from);