diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 515b0b7..0674a83 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -794,7 +794,7 @@
 component_test_zlib_make() {
     msg "build: zlib enabled, make"
     scripts/config.pl set MBEDTLS_ZLIB_SUPPORT
-    make ZLIB=1 CFLAGS='-Werror -O1'
+    make ZLIB=1 CFLAGS='-Werror -O2'
 
     msg "test: main suites (zlib, make)"
     make test
@@ -1442,7 +1442,7 @@
 }
 
 component_test_m32_o0 () {
-    # Build once with -O0, to compile out the i386 specific inline assembly
+    # Build without optimization, to not use the i386 specific inline assembly.
     msg "build: i386, make, gcc -O0 (ASan build)" # ~ 30s
     scripts/config.pl full
     make CC=gcc CFLAGS="$ASAN_CFLAGS -m32 -O0" LDFLAGS="-m32 $ASAN_CFLAGS"
@@ -1457,16 +1457,17 @@
     esac
 }
 
-component_test_m32_o1 () {
-    # Build again with -O1, to compile in the i386 specific inline assembly
-    msg "build: i386, make, gcc -O1 (ASan build)" # ~ 30s
+component_test_m32_o2 () {
+    # Build with optimization, to use the i386 specific inline assembly
+    # and go faster for tests.
+    msg "build: i386, make, gcc -O2 (ASan build)" # ~ 30s
     scripts/config.pl full
-    make CC=gcc CFLAGS="$ASAN_CFLAGS -m32 -O1" LDFLAGS="-m32 $ASAN_CFLAGS"
+    make CC=gcc CFLAGS="$ASAN_CFLAGS -m32 -O2" LDFLAGS="-m32 $ASAN_CFLAGS"
 
-    msg "test: i386, make, gcc -O1 (ASan build)"
+    msg "test: i386, make, gcc -O2 (ASan build)"
     make test
 
-    msg "test ssl-opt.sh, i386, make, gcc-O1"
+    msg "test ssl-opt.sh, i386, make, gcc-O2"
     if_build_succeeded tests/ssl-opt.sh
 }
 support_test_m32_o1 () {