diff --git a/src/components/drive.c b/src/components/drive.c
index 24d92c3..fd5efb8 100644
--- a/src/components/drive.c
+++ b/src/components/drive.c
@@ -60,7 +60,7 @@ void nn_drive_writeSector(nn_drive *drive, void *_, nn_component *component, nn_
     int sector = nn_toInt(sectorValue);
     size_t sector_size = drive->getSectorSize(component, drive->userdata);
     nn_value bufValue = nn_getArgument(computer, 1);
-    char *buf = nn_toString(bufValue, &sector_size);
+    const char *buf = nn_toString(bufValue, &sector_size);
     drive->writeSector(component, drive->userdata, sector, buf);
 }
 void nn_drive_readByte(nn_drive *drive, void *_, nn_component *component, nn_computer *computer) {
@@ -71,7 +71,7 @@ void nn_drive_readByte(nn_drive *drive, void *_, nn_component *component, nn_com
     size_t sector_offset = disk_offset % sector_size;
 
     char buf[sector_size];
-    drive->readSector(component, drive->userdata, sector, &buf);
+    drive->readSector(component, drive->userdata, sector, buf);
 
     nn_return(computer, nn_values_integer(buf[sector_offset]));
 }
@@ -85,7 +85,7 @@ void nn_drive_writeByte(nn_drive *drive, void *_, nn_component *component, nn_co
     size_t sector_offset = disk_offset % sector_size;
 
     char buf[sector_size];
-    drive->readSector(component, drive->userdata, sector, &buf);
+    drive->readSector(component, drive->userdata, sector, buf);
 
     buf[sector_offset] = write;
 
diff --git a/src/emulator.c b/src/emulator.c
index 2aa40bf..4474d79 100644
--- a/src/emulator.c
+++ b/src/emulator.c
@@ -51,6 +51,10 @@ const char *ne_location(nn_address address) {
 
 size_t ne_eeprom_get(nn_component *component, void *_, char *buf) {
     FILE *f = fopen(ne_location(nn_getComponentAddress(component)), "rb");
+    if (f == NULL) {
+        printf("couldn't read eeprom");
+        exit(1);
+    }
     fseek(f, 0, SEEK_END);
     size_t len = ftell(f);
     fseek(f, 0, SEEK_SET);
@@ -61,6 +65,10 @@ size_t ne_eeprom_get(nn_component *component, void *_, char *buf) {
 
 void ne_eeprom_set(nn_component *component, void *_, const char *buf, size_t len) {
     FILE *f = fopen(ne_location(nn_getComponentAddress(component)), "wb");
+    if (f == NULL) {
+        printf("couldn't write eeprom");
+        exit(1);
+    }
     fwrite(buf, sizeof(char), len, f);
     fclose(f);
 }