diff --git a/base/Rules.mk b/base/Rules.mk
index 8de9f0d..0bfe4c7 100644
--- a/base/Rules.mk
+++ b/base/Rules.mk
@@ -7,7 +7,7 @@ TOOL_PREFIX = m68k-unknown-elf-
 CC = $(TOOL_PREFIX)gcc
 OBJCOPY = $(TOOL_PREFIX)objcopy
 PYTHON = python3
-GZIP = zopfli
+GZIP = zopfli --i32
 #GZIP = gzip -fk9
 
 ifneq ($(VERBOSE),1)
diff --git a/inflate/pack_exe.py b/inflate/pack_exe.py
index d755235..fc25613 100644
--- a/inflate/pack_exe.py
+++ b/inflate/pack_exe.py
@@ -40,7 +40,7 @@
 MIN_COMPRESSION = 8
 
 # Command for creating gzip files.
-GZIP = "zopfli"
+GZIP = "zopfli --i32"
 #GZIP = "gzip -fk9"
 
 # Prefix for intermediate (temporary) files.
diff --git a/inflate/test_inflate.py b/inflate/test_inflate.py
index c4e411b..4407b94 100644
--- a/inflate/test_inflate.py
+++ b/inflate/test_inflate.py
@@ -11,7 +11,7 @@
 import struct, sys, os
 
 # Command for creating gzip files.
-GZIP = "zopfli -c"
+GZIP = "zopfli --i32 -c"
 #GZIP = "gzip -c9"
 
 HUNK_HEADER = 0x3f3