I've just found the way to solve this problem out.
1. Use Victor to flash the phone with T720_G_05.05.015R_full_flash.vfl
2. Use PST to flash it with T720_G_05.07.29R_flash.shx
3. Use Victor to flex it with T720_Manufacturing_Flex_Model_GM5T0AA052.vhs
4. Use PST to flex it with SE4567AXXB1125.hs
Right before the flex SE4567AXXB1125.hs was forced into the phone, it (the phone) could be easily detected by any software via a USB cable. Afterwards, it couldn't be detected.
==> maybe this flex causes troubles.