diff --git a/ext/eyalroz/module.lb b/ext/eyalroz/module.lb
index 8f37ffb357..080a6d19c0 100644
--- a/ext/eyalroz/module.lb
+++ b/ext/eyalroz/module.lb
@@ -23,10 +23,14 @@ def build(env):
 
     env.copy("printf/src/printf/printf.h", "printf.h")
     files = env.copy("printf/src/printf/printf.c", "printf.c")
-    env.collect(":build:ccflags", "-Wno-double-promotion", "-Wno-overflow", operations=files)
+    env.collect(":build:ccflags", "-Wno-overflow", operations=files)
 
     with_long_long = "avr" not in env[":target"].identifier.platform
+    with_double = "fd" in env[":target"].get_driver("core")["type"]
+    if not with_double:
+        env.collect(":build:ccflags", "-Wno-double-promotion", operations=files)
     env.substitutions = {
+        "with_double": with_double,
         "with_long_long": env.get(":io:with_long_long", with_long_long),
         "is_hosted": env[":target"].identifier.platform == "hosted",
     }
diff --git a/ext/eyalroz/printf b/ext/eyalroz/printf
index 72716295bc..9bd8ed1b06 160000
--- a/ext/eyalroz/printf
+++ b/ext/eyalroz/printf
@@ -1 +1 @@
-Subproject commit 72716295bcaa14f96ad9725b40dcc9dff0930eac
+Subproject commit 9bd8ed1b06dca8db465d9dc285a673ec97346421
diff --git a/ext/eyalroz/printf_config.h.in b/ext/eyalroz/printf_config.h.in
index 758cb54603..a0ddd0a158 100644
--- a/ext/eyalroz/printf_config.h.in
+++ b/ext/eyalroz/printf_config.h.in
@@ -20,19 +20,17 @@
 #endif
 
 #ifndef PRINTF_DEFAULT_FLOAT_PRECISION
-#define PRINTF_DEFAULT_FLOAT_PRECISION  5
+#define PRINTF_DEFAULT_FLOAT_PRECISION 5
 #endif
 
-#ifndef PRINTF_ALIAS_STANDARD_FUNCTION_NAMES
-#define PRINTF_ALIAS_STANDARD_FUNCTION_NAMES {{ 0 if is_hosted else 1 }}
+#ifndef PRINTF_USE_DOUBLE_INTERNALLY
+#define PRINTF_USE_DOUBLE_INTERNALLY {{ 1 if with_double else 0 }}
 #endif
 
 #ifndef PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_HARD
-#define PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_HARD 0
+#define PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_HARD {{ 0 if is_hosted else 1 }}
 #endif
 
 #ifndef PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_SOFT
 #define PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_SOFT 0
 #endif
-
-