diff --git a/usr.sbin/bhyve/aarch64/bhyverun_machdep.c b/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
--- a/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
+++ b/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
@@ -270,7 +270,7 @@
 	return (0);
 }
 
-static bool
+static int
 init_mmio_uart(struct vmctx *ctx)
 {
 	struct uart_pl011_softc *sc;
@@ -280,14 +280,14 @@
 
 	path = get_config_value("console");
 	if (path == NULL)
-		return (false);
+		return (1);
 
 	sc = uart_pl011_init(mmio_uart_intr_assert, mmio_uart_intr_deassert,
 	    ctx);
 	if (uart_pl011_tty_open(sc, path) != 0) {
 		EPRINTLN("Unable to initialize backend '%s' for mmio uart",
 		    path);
-		assert(0);
+		return (-1);
 	}
 
 	bzero(&mr, sizeof(struct mem_range));
@@ -301,7 +301,7 @@
 	error = register_mem(&mr);
 	assert(error == 0);
 
-	return (true);
+	return (0);
 }
 
 static void
@@ -414,8 +414,11 @@
 		return (error);
 	}
 
-	if (init_mmio_uart(ctx))
+	error = init_mmio_uart(ctx);
+	if (error == 0)
 		fdt_add_uart(UART_MMIO_BASE, UART_MMIO_SIZE, UART_INTR);
+	else if (error < 0)
+		return (error);
 	init_mmio_rtc(ctx);
 	fdt_add_rtc(RTC_MMIO_BASE, RTC_MMIO_SIZE, RTC_INTR);
 	fdt_add_timer();