The G33M SMARC SOM (i.MX8MQ) supports USDHC1 and USDHC2 as boot media. But our default configuration SOM supports only USDHC1 (eMMC) as boot media. USDHC2 is muxed between Standard SD and on SOM WiFi.
Hence, to boot from SD please contact iWave representative.
For further inquiries, please get in touch with mktg@iwave-global.com
Please find the detailed G33M product information in the below link,