COMFAST CF-WR650AC V2: root password required after fresh OpenWrt 25.12.6 installation

[DANLAB INVESTMENTS]

Hello OpenWrt Developers,

I successfully flashed my COMFAST CF-WR650AC V2 using the
manufacturer's web interface with the official OpenWrt 25.12.6 image.

Device details:
- Model: COMFAST CF-WR650AC V2
- CPU: Qualcomm Atheros QCA9558
- RAM: 256 MB DDR2
- Flash: 16 MB
- PCB revision: R120QH_VER1.2
- Previous OEM firmware: V2.6.1
- Image: openwrt-25.12.6-ath79-generic-comfast_cf-wr650ac-v2-squashfs-sysupgrade.bin

The router boots and responds at 192.168.1.1. LuCI loads at
http://192.168.1.1/cgi-bin/luci/, but root login with an empty
password fails. SSH also asks for a root password.

I understand that an official fresh OpenWrt installation normally has
no root password.

Could you please clarify:
1. Is any default root password expected for this model or image?
2. Can the original COMFAST configuration/password persist when
flashing from OEM firmware?
3. Is this a known issue with CF-WR650AC V2 or OpenWrt 25.12.6?
4. What is the recommended method to regain root access without reflashing?
5. How can failsafe mode reliably be triggered on this device if the
LEDs do not behave consistently?

Thank you for any guidance.

Best regards,
Dimitri