Tool/software: Linux
eMMC - RPMB is supported by eMMC version 4.4 or later.
According to chapter 18.11 of AM335x Sitara™ Processors - Technical Reference Manual
- Literature Number: SPRUH73M
- October 2011–Revised January 2016
The AM335x only supports full compliance with MMC standard spec. v4.3. IOW, AM335x does not support eMMC - RPMB function
Please correct me if I am wrong.