[BUG] Ultimaker 2+ shall have BLOCK_BUFFER_SIZE of 8 instead of 16 when SD is enabled only

[James4Ever0]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

Marlin will exit abnormally, with no error message and restart when printing from SD card.

Additional information

https://community.ultimaker.com/topic/44413-marlin-2121-on-um2-stops-and-reboots-when-starting-print/

https://github.com/MarlinFirmware/Configurations/blob/release-2.1.2.5/config/examples/Ultimaker/Ultimaker%202%2B/Configuration_adv.h