I have the same problem as you guys have, got a SDS 1152CML+ stuck on boot screen.
Tried multiple times the math button reset but has not worked.
None of the buttons working - could someone help me with the usb reset?
Inserting memory stick into front usb socket gets a response but utility key press button not
working. Rear usb connection yields -
Siglent,SDS1152CML+,SDS1MHED4R5827,6.01.01.21R2\n
Correct make,model and serial number