Hello…
Last week I updated from 6.15 to 6.17 a routerboard (Sxt), and it was all fine.
After off and on electricity,
a routerboard didn’t was normal: IP and MAC were blanked,
being impossible accessing it by winbox or netinstall.
How can I do in this case?
Hi… 
A month ago I also got the same 2.4GHz RouterBoard SXT and in desktop testing in laboratory
the RouterBoard had the same problem, when on the RouterBoard and accessing the IP and Mac WinBox was blank or hidden, being impossible to access the configuration.
However I contacted the vendor of the product who changed the equipment.
regards.
Disable firewall on your PC
Hello… 
friend
His argument did not work in the laboratory.
regards…
Francisco |Macr@Soft|ViaSuporte|vianternet|São Paulo|Brasil|
shocked
information: RMA MikroTik | Krisjanis |
there are two level beeps. First single beep indicates that router has gotten to
bios stage successfully.
Second double beep indicates that RouterOS has loaded
successfully. Does it pass both?
information: User
yes,first single beep has sucess, the second not.
information: RMA MikroTik | Krisjanis |
I see, then if reinstallation via Netinstall is impossible you should return this
unit to your supplier for warranty service.
(^~^) 100 More.
Conclusion: Recent upgrades 6:15 and 6:17 were damaged and caused fatal errors in normal handsets,
which received the upgrade firmware 6.15 and 6.17.
*** ALL TEST OK *** the best firmware 6.12
100 more
Great to tell us
Goodluck!
Hi…
° 6.18 upgrade corrected the errors found in version 6.15 to 6.17.
patch updated in NetInstall
regard. viasuporte São Paulo-Brasil