Hi, Tplink!

Hi it's me again, I once installed beta firmware 1.7.0 to my m4r v2 and it didn't work. It said that the firmware was incorrect, I tried installing it both from webUI and firmware recovery mode. Both failed. But I see from this forum there are some who have the same hardware as me M4R V2, they managed to install beta firmware 1.7.0 why can't mine?

Note i have 4 deco, E4 v1 3 pcs, M4 v2 (1.6.5 firmware) 1 pcs. Since the E4 had the new 1.7.0 update and can do connection preference, thats why i want my m4 can do the same..