Index: uspace/drv/infrastructure/rootamdm37x/rootamdm37x.c
===================================================================
--- uspace/drv/infrastructure/rootamdm37x/rootamdm37x.c	(revision 19acf24d58c72e5acd9143fc337c64403df0b556)
+++ uspace/drv/infrastructure/rootamdm37x/rootamdm37x.c	(revision bf6f6ca1708b1b5db9e07d5f0c22a2b04401830c)
@@ -340,4 +340,10 @@
 static int usb_tll_init(amdm37x_t *device)
 {
+	/* Check access */
+	if (pio_read_32(&device->cm.core->idlest3) & CORE_CM_IDLEST3_ST_USBTLL_FLAG) {
+		ddf_msg(LVL_ERROR, "USB TLL is not accessible");
+		return EIO;
+	}
+
 	/* Reset USB TLL */
 	pio_set_32(&device->tll->sysconfig, TLL_SYSCONFIG_SOFTRESET_FLAG, 5);