fix(eth): Use correct ETH MAC address by me-no-dev · Pull Request #11958 · espressif/arduino-esp32

me-no-dev · 2025-10-27T23:10:22Z

This pull request updates the method used to retrieve the MAC address for Ethernet interfaces in the ETHClass::beginSPI function. The change improves hardware compatibility and clarifies error logging.

Hardware compatibility and error handling improvements:

In ETH.cpp, replaced the call to esp_efuse_mac_get_default with esp_read_mac(base_mac_addr, ESP_MAC_ETH) to use the correct API for obtaining the Ethernet MAC address, and updated the log message to clarify the source of failure.

github-actions · 2025-10-27T23:11:06Z

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github-actions · 2025-10-27T23:16:11Z

Memory usage test (comparing PR against master branch)

The table below shows the summary of memory usage change (decrease - increase) in bytes and percentage for each target.

Memory	FLASH [bytes]		FLASH [%]		RAM [bytes]		RAM [%]
Target	DEC	INC	DEC	INC	DEC	INC	DEC	INC
ESP32C5	0	⚠️ +1256	0.00	⚠️ +0.21	0	⚠️ +112	0.00	⚠️ +0.51
ESP32P4	💚 -2	⚠️ +1020	0.00	⚠️ +0.17	0	⚠️ +40	0.00	⚠️ +0.15
ESP32S3	0	⚠️ +908	0.00	⚠️ +0.16	0	⚠️ +64	0.00	⚠️ +0.25
ESP32S2	0	⚠️ +976	0.00	⚠️ +0.19	0	⚠️ +48	0.00	⚠️ +0.23
ESP32C3	0	⚠️ +1136	0.00	⚠️ +0.20	0	⚠️ +64	0.00	⚠️ +0.36
ESP32C6	0	⚠️ +1246	0.00	⚠️ +0.23	0	⚠️ +112	0.00	⚠️ +0.58
ESP32H2	0	⚠️ +1096	0.00	⚠️ +0.19	0	⚠️ +88	0.00	⚠️ +0.46
ESP32	0	⚠️ +976	0.00	⚠️ +0.18	0	⚠️ +32	0.00	⚠️ +0.12

Click to expand the detailed deltas report [usage change in BYTES]

Target	ESP32C5		ESP32P4		ESP32S3		ESP32S2		ESP32C3		ESP32C6		ESP32H2		ESP32
Example	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM
libraries/Ethernet/examples/ETH_W5500_Arduino_SPI	⚠️ +1256	⚠️ +112	⚠️ +1020	⚠️ +40	⚠️ +876	⚠️ +64	⚠️ +976	⚠️ +48	⚠️ +1136	⚠️ +64	⚠️ +1246	⚠️ +112	⚠️ +1096	⚠️ +88	⚠️ +964	⚠️ +32
libraries/Ethernet/examples/ETH_W5500_IDF_SPI	⚠️ +1256	⚠️ +112	⚠️ +1020	⚠️ +40	⚠️ +908	⚠️ +64	⚠️ +944	⚠️ +48	⚠️ +1136	⚠️ +64	⚠️ +1246	⚠️ +112	⚠️ +1096	⚠️ +88	⚠️ +976	⚠️ +32
libraries/Ethernet/examples/ETH_WIFI_BRIDGE	⚠️ +2	0	💚 -2	0	⚠️ +4	0	⚠️ +4	0	⚠️ +2	0	⚠️ +2	0	-	-	0	0
libraries/Ethernet/examples/ETH_TLK110	-	-	0	0	-	-	-	-	-	-	-	-	-	-	0	0
libraries/Ethernet/examples/ETH_LAN8720	-	-	-	-	-	-	-	-	-	-	-	-	-	-	0	0

github-actions · 2025-10-27T23:17:47Z

Test Results

76 files 76 suites 16m 50s ⏱️
38 tests 38 ✅ 0 💤 0 ❌
241 runs 241 ✅ 0 💤 0 ❌

Results for commit 88877e5.

♻️ This comment has been updated with latest results.

TD-er · 2025-10-28T07:59:52Z

Tried it and it is working fine.
On my ESP32-S3 board with W5500 SPI Ethernet it now is assigned
DA:54:75:CB:C3:ED, where it was DE:54:75:CB:C3:EC before. (The same as WIFI_SOFTAP, which is the "locally administred" of WIFI_STA)

Just for completeness, these are the MAC-addresses as stored in the EFUSE MAC of the ESP:

DC:54:75:CB:C3:EC      ESP_MAC_WIFI_STA,      /**< MAC for WiFi Station (6 bytes) */
DE:54:75:CB:C3:EC      ESP_MAC_WIFI_SOFTAP,   /**< MAC for WiFi Soft-AP (6 bytes) */
DC:54:75:CB:C3:ED      ESP_MAC_BT,            /**< MAC for Bluetooth (6 bytes) */
DE:54:75:CB:C3:ED      ESP_MAC_ETH,           /**< MAC for Ethernet (6 bytes) */
00:00:00:00:00:00      ESP_MAC_IEEE802154,    /**< if CONFIG_SOC_IEEE802154_SUPPORTED=y, MAC for IEEE802154 (8 bytes) */
DC:54:75:CB:C3:EC      ESP_MAC_BASE,          /**< Base MAC for that used for other MAC types (6 bytes) */
DC:54:75:CB:C3:EC      ESP_MAC_EFUSE_FACTORY, /**< MAC_FACTORY eFuse which was burned by Espressif in production (6 bytes) */
00:00:00:00:00:00      ESP_MAC_EFUSE_CUSTOM,  /**< MAC_CUSTOM eFuse which was can be burned by customer (6 bytes) */
00:00:00:00:00:00      ESP_MAC_EFUSE_EXT      /**< if CONFIG_SOC_IEEE802154_SUPPORTED=y, MAC_EXT eFuse which is used as an extender for IEEE802154 MAC (2 bytes) */

So it used DE:54:75:CB:C3:ED (ESP_MAC_ETH) and since bit 2 of the first octet was already set, it XOR'ed DE with 0x04 -> DA.

esp_err_t esp_derive_local_mac(uint8_t *local_mac, const uint8_t *universal_mac);

Derive local MAC address from universal MAC address.
This function copies a universal MAC address and then sets the "locally
administered" bit (bit 0x2) in the first octet, creating a locally administered MAC address.

If the universal MAC address argument is already a locally administered MAC address, then the first octet is XORed with 0x4 in order to create a different locally administered MAC address.

N.B. This also fixes (yet) unknown issues like why SPI Ethernet would probably not work on an ESP32-P4 as those have the first 3 MAC addresses set to 0. (probably same for ESP32-H2)

arendst · 2025-10-28T13:06:43Z

Pls also chk if the response from ETH.macAddress() is also the correct one.

While testing this fix I still see no difference between the WiFi MAC and the Ethernet Mac

14:01:56.205     "Hostname":"esp32p4",
14:01:56.205     "IPAddress":"192.168.2.226",
14:01:56.205     "Gateway":"192.168.2.254",
14:01:56.205     "Subnetmask":"255.255.255.0",
14:01:56.205     "DNSServer1":"192.168.2.24",
14:01:56.205     "DNSServer2":"192.168.2.25",
14:01:56.205     "Mac":"30:ED:A0:E1:F2:B8",
14:01:56.205     "IP6Global":"fd84:7996:2cbf:1349:b63a:45ff:fe83:3a34",
14:01:56.205     "IP6Local":"fe80::b63a:45ff:fe83:3a34%st3",
14:01:56.205     "Ethernet":{
14:01:56.205       "Hostname":"esp32p4-eth",
14:01:56.205       "IPAddress":"192.168.2.143",
14:01:56.205       "Gateway":"192.168.2.254",
14:01:56.205       "Subnetmask":"255.255.255.0",
14:01:56.205       "DNSServer1":"192.168.2.24",
14:01:56.205       "DNSServer2":"192.168.2.25",
14:01:56.205       "Mac":"30:ED:A0:E1:F2:B8",
14:01:56.205       "IP6Global":"fd84:7996:2cbf:1349:32ed:a0ff:fee1:f2b8",
14:01:56.205       "IP6Local":"fe80::32ed:a0ff:fee1:f2b8%en1"
14:01:56.205     }

me-no-dev · 2025-10-28T13:32:02Z

@arendst you are running on P4 that does not have WiFi. Do not trust the MAC address that you get. The C6 that gives you WiFi has a different MAC address

arendst · 2025-10-28T13:40:43Z

You're right. Verified on C3 with ethernet. Thx.

fix(eth): Use correct ETH MAC address

88877e5

me-no-dev added the Status: Review needed Issue or PR is awaiting review label Oct 27, 2025

P-R-O-C-H-Y approved these changes Oct 29, 2025

View reviewed changes

me-no-dev added Status: Pending Merge Pull Request is ready to be merged and removed Status: Review needed Issue or PR is awaiting review labels Nov 3, 2025

me-no-dev merged commit e2aa34f into master Nov 3, 2025
86 of 89 checks passed

me-no-dev deleted the bugfix/eth_mac branch November 3, 2025 12:58

TD-er mentioned this pull request Dec 8, 2025

Currently the MCU info is very generic. thelastoutpostworkshop/ESPConnect#50

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fix(eth): Use correct ETH MAC address#11958

fix(eth): Use correct ETH MAC address#11958
me-no-dev merged 1 commit intomasterfrom
bugfix/eth_mac

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