diff --git a/include/device.h b/include/device.h
index 9df09ce1..d277c36e 100644
--- a/include/device.h
+++ b/include/device.h
@@ -66,7 +66,7 @@ void fm_csn_low(void);
  */
 void fm_csn_high(void);
 #if NFC_CHIP == NFC_CHIP_FM11NC
-void spi_transmit(uint8_t *buf, uint8_t len);
+void spi_transmit(const uint8_t *buf, uint8_t len);
 void spi_receive(uint8_t *buf, uint8_t len);
 #elif NFC_CHIP == NFC_CHIP_FM11NT
 void i2c_start(void);
diff --git a/include/nfc.h b/include/nfc.h
index a5f5ad15..61db157b 100644
--- a/include/nfc.h
+++ b/include/nfc.h
@@ -27,6 +27,9 @@
 #define FM_REG_NFC_CFG       0xD
 #define FM_REG_REGU_CFG      0xE
 
+#define FM_EEPROM_ATQA       0x03A0
+#define FM_EEPROM_ATS        0x03B0
+
 #define RF_STATE_MASK 0xE0
 
 #elif NFC_CHIP == NFC_CHIP_FM11NT
diff --git a/interfaces/NFC/fm.c b/interfaces/NFC/fm.c
index 33d081e3..a94c8d44 100644
--- a/interfaces/NFC/fm.c
+++ b/interfaces/NFC/fm.c
@@ -121,16 +121,16 @@ void fm_write_fifo(uint8_t *buf, uint8_t len) {
 void fm11_init(void) {
 #if NFC_CHIP == NFC_CHIP_FM11NC
   uint8_t buf[7];
-  uint8_t data1[] = {0x44, 0x00, 0x04, 0x20};
-  uint8_t data2[] = {0x05, 0x72, 0x02, 0x00, 0xB3, 0x99, 0x00};
+  uint8_t atqa_sak[] = {0x44, 0x00, 0x04, 0x20};
+  uint8_t ats[] = {0x05, 0x72, 0x02, 0x00, 0xB3, 0x99, 0x00};
   do {
-    fm_write_eeprom(0x3A0, data1, sizeof(data1));
-    fm_read_eeprom(0x3A0, buf, sizeof(data1));
-  } while (memcmp(data1, buf, sizeof(data1)) != 0);
+    fm_write_eeprom(FM_EEPROM_ATQA, atqa_sak, sizeof(atqa_sak));
+    fm_read_eeprom(FM_EEPROM_ATQA, buf, sizeof(atqa_sak));
+  } while (memcmp(atqa_sak, buf, sizeof(atqa_sak)) != 0);
   do {
-    fm_write_eeprom(0x3B0, data2, sizeof(data2));
-    fm_read_eeprom(0x3B0, buf, sizeof(data2));
-  } while (memcmp(data2, buf, sizeof(data2)) != 0);
+    fm_write_eeprom(FM_EEPROM_ATS, ats, sizeof(ats));
+    fm_read_eeprom(FM_EEPROM_ATS, buf, sizeof(ats));
+  } while (memcmp(ats, buf, sizeof(ats)) != 0);
 #elif NFC_CHIP == NFC_CHIP_FM11NT
   uint8_t crc_buffer[13];
   const uint8_t user_cfg[] = {0x91, 0x82, 0x21, 0xCD};