I also faced the same issue but fortunately for me, Magisk just miraculously appeared on the phone and I successfully root the phoneI also have the problem that Magisk can't be installed with Evo 13. THe usual way it's not working (due to broken boot / recovery as mentioned here earlier).
Options i tried:
- fastboot flash boot recovery.img (img from entry post). reboot to recovery. Magisk can be installed, but phone does not start (of course, it's a wrong boot file).
Do i miss something?
I also patched the correct boot.img with magisk and flashed this boot.img (magisk_patched_..... .img) but also here no luck. Phone starts, Magisk says not installed).