Actually, we do use the BOOTLOADER(5.0.4) when shipping out.
BUT, the FW(2.9.42).  << NOTE: NOT 2.11.92 latest
since after this version of FW, All PA parameters will reset to zero when after F1+F3+F5 FULL reset. it's unfriendly for our beginner customers.

If you like, you can upgrade to 2.11.92 in a few seconds by a USB disk.
we also provide this upgrading demo video.
Make sure you know well about this RS-918, otherwise, do NOT change the IMPORTANT PA settings.