What could it be?
Firmware package: CA6S-H3721G-N-KESF-180116V28
BROM version[1]: 7.2045.2.0
DA: MTK_AllInOne_DA.bin
hash: 7a3c72dad63c06bd1a67cce0354e7286cf26ab6a, size: 15.07 MiB
version: 3.3001.2020-11-02021/09/24 09:17:37, start addr: 0x40000800
Connecting to BootROM...
Power off the phone, disconnect and reconnect the battery(if possible) and connect USB cable...
Scanning BootROM or Preloader port... Done
Detected [BootROM] MediaTek USB Port (COM21)
Connection status: XHCI:HUB3:HUB3[#4]:USB 1.10 Full-Speed
USB Driver: [MediaTek Inc.] wdm_usb, version: 3.0.1504.0, date: 1-22-2015
Platform: 0x0321 [MT6737], hw sub code: 0x8A00, hw ver: 0xCC00, sw ver: 0x0000
security config: 0x05
secure boot: yes
serial link authorization: no
download agent authorization: yes
Disabling watchdog timer... Done
Bypassing security config... error: exploit failed, no acknowledge.