diff --git a/builder/frameworks/realtek-ambz-sdk.py b/builder/frameworks/realtek-ambz-sdk.py
index 7a4c347..d91f08d 100644
--- a/builder/frameworks/realtek-ambz-sdk.py
+++ b/builder/frameworks/realtek-ambz-sdk.py
@@ -238,7 +238,8 @@ env.Append(
         "_wps",
         "_p2p",
         "_dct",
-        "_rtlstd",
+        # use lib_rtlstd.a without some __aeabi functions
+        "_rtlstd_patch",
         "m",
         "c",
         "nosys",
diff --git a/builder/utils.py b/builder/utils.py
index b7cd086..8140fff 100644
--- a/builder/utils.py
+++ b/builder/utils.py
@@ -49,6 +49,7 @@ def env_add_defaults(env, family_name: str, sdk_name: str):
         ],
         LIBPATH=[
             "$LD_DIR",
+            "$FIXUPS_DIR",
         ],
         CPPDEFINES=[
             ("LIBRETUYA", "1"),
diff --git a/platform/realtek-ambz/fixups/lib_rtlstd_patch.a b/platform/realtek-ambz/fixups/lib_rtlstd_patch.a
new file mode 100644
index 0000000..59a85f2
Binary files /dev/null and b/platform/realtek-ambz/fixups/lib_rtlstd_patch.a differ
diff --git a/platform/realtek-ambz/fixups/lib_rtlstd_patch.md b/platform/realtek-ambz/fixups/lib_rtlstd_patch.md
new file mode 100644
index 0000000..fb20c12
--- /dev/null
+++ b/platform/realtek-ambz/fixups/lib_rtlstd_patch.md
@@ -0,0 +1,14 @@
+# lib_rtlstd_patch.a
+
+```
+arm-none-eabi-gcc-ar xo lib_rtlstd.a
+arm-none-eabi-objcopy -N __aeabi_fsub rtl_eabi_cast_ram.o
+arm-none-eabi-objcopy -N __aeabi_fadd rtl_eabi_cast_ram.o
+arm-none-eabi-objcopy -N __aeabi_ui2f rtl_eabi_cast_ram.o
+arm-none-eabi-objcopy -N __aeabi_i2f rtl_eabi_cast_ram.o
+arm-none-eabi-objcopy --strip-debug --strip-unneeded ram_libc.o
+arm-none-eabi-objcopy --strip-debug --strip-unneeded ram_libgloss_retarget.o
+arm-none-eabi-objcopy --strip-debug --strip-unneeded rtl_eabi_cast_ram.o
+arm-none-eabi-objcopy --strip-debug --strip-unneeded rtl_math_ram.o
+arm-none-eabi-gcc-ar qs lib_rtlstd_patch.a *.o
+```