Try a different USB cable and a on your PC, as USB 3.0/3.1 ports can occasionally cause timing issues during DA initialization.
Connect your powered-off device while holding the Volume buttons. sp flash tool error status ext ram exception
Check the sticker under your phone battery or on the original box for the exact model number. Try a different USB cable and a on your PC, as USB 3
The most frequent cause is a "near-miss" in firmware selection. Confirm your device's exact model number and region. sp flash tool error status ext ram exception