diff --git a/CMakeLists.txt b/CMakeLists.txt
index e927b66e9..a900b9929 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -158,8 +158,9 @@ elseif(SD845)
     set(CMAKE_ASM_FLAGS  "-marm -march=armv8.2-a+simd+crypto -mtune=cortex-a75.cortex-a55 -mfpu=neon-fp-armv8 -mfloat-abi=hard")
 elseif(SD865)
     add_definitions(-DSD865)
-    add_definitions(-marm -march=armv8.2-a+simd+crypto -mtune=cortex-a77.cortex-a55 -mfpu=neon-fp-armv8 -mfloat-abi=hard)
-    set(CMAKE_ASM_FLAGS  "-marm -march=armv8.2-a+simd+crypto -mtune=cortex-a77.cortex-a55 -mfpu=neon-fp-armv8 -mfloat-abi=hard")
+    #note that cortex-a77.cortex-a55 is not supported, so fall back to a76 instead
+    add_definitions(-marm -march=armv8.2-a+simd+crypto -mtune=cortex-a76.cortex-a55 -mfpu=neon-fp-armv8 -mfloat-abi=hard)
+    set(CMAKE_ASM_FLAGS  "-marm -march=armv8.2-a+simd+crypto -mtune=cortex-a76.cortex-a55 -mfpu=neon-fp-armv8 -mfloat-abi=hard")
 elseif(SD888)
     add_definitions(-DSD888)
     add_definitions(-marm -march=armv8.4-a+simd+crypto -mfpu=neon-fp-armv8 -mfloat-abi=hard)