diff --git a/client/emv/cmdemv.h b/client/emv/cmdemv.h
index 0b0419b07..c91f75606 100644
--- a/client/emv/cmdemv.h
+++ b/client/emv/cmdemv.h
@@ -25,6 +25,7 @@
 #include "cmdmain.h"
 #include "emvcore.h"
 #include "apduinfo.h"
+#include "emv_roca.h"
 
 int CmdEMV(const char *Cmd);
 
diff --git a/client/emv/emv_roca.c b/client/emv/emv_roca.c
index 48845c99f..fe68b83ce 100644
--- a/client/emv/emv_roca.c
+++ b/client/emv/emv_roca.c
@@ -73,7 +73,7 @@ mbedtls_mpi_uint mpi_get_uint(const mbedtls_mpi *X) {
 	return 0;
 }
 
-bool emv_rocacheck(char *modulus) {
+bool emv_rocacheck(const unsigned char *buf, size_t buflen) {
 
 	mbedtls_mpi *t_modulus = NULL;
 	mbedtls_mpi_init(t_modulus);
@@ -82,8 +82,7 @@ bool emv_rocacheck(char *modulus) {
 
 	rocacheck_init();
 
-	// 
-	MBEDTLS_MPI_CHK( mbedtls_mpi_read_string(t_modulus, 10, modulus) );
+	MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary(t_modulus, buf, buflen) );
 	
 	
 	for (int i = 0; i < ROCA_PRINTS_LENGTH; i++) {
diff --git a/client/emv/emv_roca.h b/client/emv/emv_roca.h
index e2ba0ac51..a42d8349e 100644
--- a/client/emv/emv_roca.h
+++ b/client/emv/emv_roca.h
@@ -35,7 +35,7 @@ void rocacheck_init(void);
 void rocacheck_cleanup(void);
 int bitand_is_zero(	mbedtls_mpi* a, mbedtls_mpi* b );
 
-extern bool emv_rocacheck( char *modulus );
+extern bool emv_rocacheck( const unsigned char *buf, size_t buflen );
 
 #endif