diff --git a/speculos/cxlib/flex-api-level-cx-21.elf b/speculos/cxlib/flex-api-level-cx-21.elf
new file mode 100644
index 00000000..c5b562f8
Binary files /dev/null and b/speculos/cxlib/flex-api-level-cx-21.elf differ
diff --git a/speculos/fonts/flex-fonts-21.bin b/speculos/fonts/flex-fonts-21.bin
new file mode 120000
index 00000000..5b76312c
--- /dev/null
+++ b/speculos/fonts/flex-fonts-21.bin
@@ -0,0 +1 @@
+flex-fonts-18.bin
\ No newline at end of file
diff --git a/src/launcher.c b/src/launcher.c
index b036b5aa..fefbe80c 100644
--- a/src/launcher.c
+++ b/src/launcher.c
@@ -824,7 +824,7 @@ int main(int argc, char *argv[])
     break;
   case MODEL_FLEX:
     if (sdk_version != SDK_API_LEVEL_18 && sdk_version != SDK_API_LEVEL_19 &&
-        sdk_version != SDK_API_LEVEL_20) {
+        sdk_version != SDK_API_LEVEL_20 && sdk_version != SDK_API_LEVEL_21) {
       errx(1, "invalid SDK version for the Ledger Flex");
     }
     break;