As further test, it seems that after the UVC stream is setup, M484 will issue TXPKIF interrupt event if EPTXCNT is not written.
Is there any doc about the HSUSBH ISO transaction of M484?

I'm implementing a UVC protocol on M484. I use manual-validation because UVC payload can only be sent in packet. The packet format is 2 bytes header + pixel payload. As my test, I use 258 as ep size for iso channel, which is 2-byte header and 128 16-bit RGB565 data. According to the log from NuConso...