Currently default pinmux is one ethernet port + sdcard + i2s + i2c + refclk + many gpio.
Actually there is a hidden pinmux in mt7628 chip, we can use ethernet x 5 + sdcard without i2c/i2s.

Very interesting, this pinmux works well on VoCore2 but do not have any clue in datasheet.
We need to remove i2c pull up resistor to make it work normal.

Its pin order:

29-GPIO0-SD_CLK
16-I2S_SDI-SD_D1
18-I2S_WS-SD_D0
19-I2S_CLK-SD_CMD
20-I2C-SCLK-SD_D3
21-I2C-SDAT-SD_D2

but also need to update driver to make it work. 🙂