diff --git a/ruby.spec b/ruby.spec
index 4635f3d..c00635e 100644
--- a/ruby.spec
+++ b/ruby.spec
@@ -911,6 +911,18 @@ DISABLE_TESTS="$DISABLE_TESTS -n !/test_segv_\(setproctitle\|test\|loaded_featur
 # https://bugs.ruby-lang.org/issues/14175
 sed -i '/def test_mdns_each_address$/,/^  end$/ s/^/#/' test/resolv/test_mdns.rb
 
+# Provide workaround for s390x zlib errors in tests on RHEL 8.
+# The library works, but there seems to be chip acceleration used
+# resulting in failing asserts against hardcoded values that were
+# created for a different algorithm than is the default on that platform.
+# Fix taken from:
+# https://github.com/ruby/zlib/commit/280a1b5905d752af25e9f09e6511388cb4260eb2
+%ifarch s390x
+  # Force chip acceleration off.
+  # https://www.ibm.com/docs/en/linux-on-systems?topic=o-applications-2
+  export DFLTCC=0
+%endif
+
 # For now, disable test incompatible with OpenSSL 1.1.1:
 # https://github.com/rubygems/rubygems/issues/2388
 DISABLE_TESTS="$DISABLE_TESTS -n !/test_do_not_allow_invalid_client_cert_auth_connection/"