I disabled signed driver requirement on Windows 10 and forced installation of ADB USB driver. This enables fastboot execution.
I repeated all steps that worked previously.
Code:
adb reboot edl
edl.exe /lQualcomm_662_loader.elf
edl.exe /u /r /pboot_a long.img
edl.exe /u /r /pboot_a short.img /c4025
--Magisk patch short.img--
adb reboot bootloader
fastboot boot magisk_patched-*.img
At this point, the device hangs and does not complete the boot.
Forcing a restart through hard-reset or "reboot" does not lead to su privileges in adb shell.
Magisk claimed the img was successfully patched, but it does not root. Flashing without root leads to frozen boot sequence.