Open Fastboot Mode On Oppo A37 Better Link: How To
If you are stuck in a "Qualcomm HS-USB QDLoader 9008" mode (black screen but PC makes a connection sound), your phone may be in an emergency download mode. To exit this, simply hold the Power button for 15 seconds.
Have you managed to enter Fastboot mode successfully? Let us know in the comments if you faced any specific hurdles! how to open fastboot mode on oppo a37 better
Do not confuse Recovery Mode with Fastboot Mode—they serve different purposes. If you are stuck in a "Qualcomm HS-USB