RB911-2Hn TX fail / wont boot...

Hi pals,

Have my package of RB911-2Hn arrived and started to implement it to users in small network.
Im satisfied with this CPE as it is relatively cheap and good allaround solution with single chain N and very usefull NV2, but Im dissapointed with very bad quality of radio parts on this board. In series of 100 pcs, there is more than 20 with tx failed in less than one month.

Any user expiriences ?
Any recomandation ?

Cant find very much resources about this board on internet. Also , in series of 100pcs, some six or seven wont boot. Is there procedure of ruteros booting from scratch without serial cable ? This board would require soldering for serial comunication and thus void any guarantie.

Thanx for any help.