diff --git a/ports/samd/samd_spiflash.c b/ports/samd/samd_spiflash.c
index 32563762f..724916f65 100644
--- a/ports/samd/samd_spiflash.c
+++ b/ports/samd/samd_spiflash.c
@@ -3,6 +3,7 @@
  *
  * The MIT License (MIT)
  *
+ * Copyright (c) 2019-2020 Peter Hinch
  * Copyright (c) 2023 Robert Hammelrath
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -23,10 +24,6 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  *
- * Based on spiflash.py by Christopher Arndt and the EEPROM library of Peter Hinch
- *
- * https://github.com/SpotlightKid/micropython-stm-lib/tree/master/spiflash
- * https://github.com/peterhinch/micropython_eeprom.git
  */
 
 #include <stdint.h>
@@ -44,14 +41,13 @@
 #define _PROGRAM_PAGE_INDEX (1)
 #define _SECTOR_ERASE_INDEX (2)
 
-const uint8_t _CMDS3BA[] = {0x03, 0x02, 0x20};  // CMD_READ CMD_PROGRAM_PAGE CMD_ERASE_4K
-const uint8_t _CMDS4BA[] = {0x13, 0x12, 0x21};  // CMD_READ CMD_PROGRAM_PAGE CMD_ERASE_4K
+const uint8_t _COMMANDS_24BIT[] = {0x03, 0x02, 0x20};  // READ, PROGRAM_PAGE, ERASE_4K
+const uint8_t _COMMANDS_32BIT[] = {0x13, 0x12, 0x21};  // READ, PROGRAM_PAGE, ERASE_4K
 
-#define CMD_JEDEC_ID (0x9F)
-#define CMD_READ_STATUS (0x05)
-#define CMD_WRITE_ENABLE (0x06)
-#define CMD_READ_UID (0x4B)
-#define CMD_READ_SFDP (0x5A)
+#define COMMAND_JEDEC_ID (0x9F)
+#define COMMAND_READ_STATUS (0x05)
+#define COMMAND_WRITE_ENABLE (0x06)
+#define COMMAND_READ_SFDP (0x5A)
 #define PAGE_SIZE (256)
 #define SECTOR_SIZE (4096)
 
@@ -59,7 +55,7 @@ typedef struct _spiflash_obj_t {
     mp_obj_base_t base;
     mp_obj_base_t *spi;
     mp_hal_pin_obj_t cs;
-    bool addr4b;
+    bool addr_is_32bit;
     uint16_t pagesize;
     uint16_t sectorsize;
     const uint8_t *commands;
@@ -81,7 +77,7 @@ static void wait(spiflash_obj_t *self) {
     // 100000 wait 500ms max. at 120Mhz. Sector erase lasts about
     // 100ms worst case, page write is < 1ms.
     do {
-        msg[0] = CMD_READ_STATUS;
+        msg[0] = COMMAND_READ_STATUS;
         mp_hal_pin_write(self->cs, 0);
         spi_transfer((mp_obj_base_t *)self->spi, 2, msg, msg);
         mp_hal_pin_write(self->cs, 1);
@@ -91,7 +87,7 @@ static void wait(spiflash_obj_t *self) {
 static void get_id(spiflash_obj_t *self, uint8_t id[3]) {
     uint8_t msg[1];
 
-    msg[0] = CMD_JEDEC_ID;
+    msg[0] = COMMAND_JEDEC_ID;
     mp_hal_pin_write(self->cs, 0);
     spi_transfer(self->spi, 1, msg, NULL);
     spi_transfer(self->spi, 3, id, id);
@@ -101,20 +97,20 @@ static void write_addr(spiflash_obj_t *self, uint8_t cmd, uint32_t addr) {
     uint8_t msg[5];
     uint8_t index = 1;
     msg[0] = cmd;
-    if (self->addr4b) {
+    if (self->addr_is_32bit) {
         msg[index++] = addr >> 24;
     }
     msg[index++] = (addr >> 16) & 0xff;
     msg[index++] = (addr >> 8) & 0xff;
     msg[index++] = addr & 0xff;
     mp_hal_pin_write(self->cs, 0);
-    spi_transfer(self->spi, self->addr4b ? 5 : 4, msg, msg);
+    spi_transfer(self->spi, self->addr_is_32bit ? 5 : 4, msg, msg);
 }
 
 static void write_enable(spiflash_obj_t *self) {
     uint8_t msg[1];
 
-    msg[0] = CMD_WRITE_ENABLE;
+    msg[0] = COMMAND_WRITE_ENABLE;
     mp_hal_pin_write(self->cs, 0);
     spi_transfer(self->spi, 1, msg, NULL);
     mp_hal_pin_write(self->cs, 1);
@@ -122,7 +118,7 @@ static void write_enable(spiflash_obj_t *self) {
 
 static void get_sfdp(spiflash_obj_t *self, uint32_t addr, uint8_t *buffer, int size) {
     uint8_t dummy[1];
-    write_addr(self, CMD_READ_SFDP, addr);
+    write_addr(self, COMMAND_READ_SFDP, addr);
     spi_transfer(self->spi, 1, dummy, NULL);
     spi_transfer(self->spi, size, buffer, buffer);
     mp_hal_pin_write(self->cs, 1);
@@ -150,7 +146,7 @@ STATIC mp_obj_t spiflash_make_new(const mp_obj_type_t *type, size_t n_args, size
     machine_pin_obj_t *cs = MP_OBJ_TYPE_GET_SLOT(&machine_pin_type, make_new)((mp_obj_t)&machine_pin_type, 2, 0, pin_args);
     self->cs = cs->pin_id;
 
-    self->addr4b = false; // initial setting.
+    self->addr_is_32bit = false; // initial setting.
     self->pagesize = PAGE_SIZE;
     self->sectorsize = SECTOR_SIZE;
     mp_hal_pin_write(self->cs, 1);
@@ -169,7 +165,7 @@ STATIC mp_obj_t spiflash_make_new(const mp_obj_type_t *type, size_t n_args, size
         self->size = 1 << id[2];
     }
 
-    // Get the addr4b flag and the sector size
+    // Get the addr_is_32bit flag and the sector size
     uint8_t buffer[128];
     get_sfdp(self, 0, buffer, 16);  // get the header
     int len = MIN(buffer[11] * 4, sizeof(buffer));
@@ -177,9 +173,9 @@ STATIC mp_obj_t spiflash_make_new(const mp_obj_type_t *type, size_t n_args, size
         int addr = buffer[12] + (buffer[13] << 8) + (buffer[14] << 16);
         get_sfdp(self, addr, buffer, len);  // Get the JEDEC mandatory table
         self->sectorsize = 1 << buffer[28];
-        self->addr4b = ((buffer[2] >> 1) & 0x03) != 0;
+        self->addr_is_32bit = ((buffer[2] >> 1) & 0x03) != 0;
     }
-    self->commands = self->addr4b ? _CMDS4BA : _CMDS3BA;
+    self->commands = self->addr_is_32bit ? _COMMANDS_32BIT : _COMMANDS_24BIT;
 
     return self;
 }