diff --git a/arch/arm/src/nrf91/nrf91_modem_os.c b/arch/arm/src/nrf91/nrf91_modem_os.c
index 75a9d41bc5d..e02f9b72b28 100644
--- a/arch/arm/src/nrf91/nrf91_modem_os.c
+++ b/arch/arm/src/nrf91/nrf91_modem_os.c
@@ -495,7 +495,7 @@ void nrf_modem_os_log(int level, const char *fmt, ...)
   va_list ap;
 
   va_start(ap, fmt);
-  syslog(level, fmt, ap);
+  vsyslog(level, fmt, ap);
   va_end(ap);
 }