diff --git a/ports/stm/common-hal/busio/SPI.c b/ports/stm/common-hal/busio/SPI.c
index 77f2b53706..047d59556d 100644
--- a/ports/stm/common-hal/busio/SPI.c
+++ b/ports/stm/common-hal/busio/SPI.c
@@ -250,7 +250,7 @@ void common_hal_busio_spi_never_reset(busio_spi_obj_t *self) {
 }
 
 bool common_hal_busio_spi_deinited(busio_spi_obj_t *self) {
-    return self->sck->pin == NULL;
+    return self->sck == NULL;
 }
 
 void common_hal_busio_spi_deinit(busio_spi_obj_t *self) {
diff --git a/ports/stm/common-hal/busio/UART.c b/ports/stm/common-hal/busio/UART.c
index d8677126ef..dc37a4e7c8 100644
--- a/ports/stm/common-hal/busio/UART.c
+++ b/ports/stm/common-hal/busio/UART.c
@@ -259,7 +259,7 @@ void common_hal_busio_uart_never_reset(busio_uart_obj_t *self) {
 }
 
 bool common_hal_busio_uart_deinited(busio_uart_obj_t *self) {
-    return self->tx->pin == NULL && self->rx->pin == NULL;
+    return self->tx == NULL && self->rx == NULL;
 }
 
 void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {