diff --git a/lib/src/asn1/CMakeLists.txt b/lib/src/asn1/CMakeLists.txt
index aa529e866..f88b0ad26 100644
--- a/lib/src/asn1/CMakeLists.txt
+++ b/lib/src/asn1/CMakeLists.txt
@@ -33,4 +33,6 @@ add_library(rrc_asn1 STATIC
         rrc_asn1_enum.cc
         asn1_utils.cc
         )
+# Compile RRC ASN1 optimized for size
+target_compile_options(rrc_asn1 PRIVATE "-Os")
 install(TARGETS rrc_asn1 DESTINATION ${LIBRARY_DIR})