diff --git a/src/neonucleus.h b/src/neonucleus.h
index 89ecf99..2a0f00b 100644
--- a/src/neonucleus.h
+++ b/src/neonucleus.h
@@ -879,7 +879,10 @@ typedef struct nn_EEPROMRequest {
 	void *state;
 	const nn_EEPROM *eeprom;
 	nn_EEPROMAction action;
-	char *buf;
+	union {
+		char *buf;
+		const char *robuf;
+	};
 	size_t buflen;
 } nn_EEPROMRequest;