Dear all,
I upgraded an hAp from 6.36.4 to 6.40.3 (using “System - Packages - check for updates” in Winbox), afterwards it was at 6.40.3, but the wireless interfaces were missing. I then tried to install the wireless package separately by dropping wireless-6.40.3-mipsbe.npk into the files window and reboot. Now the device is in a boot loop. So far, so bad 
… but neither a factory reset (hold reset until SFP led is flashing), nor netboot (hold reset until SFP led goes finally off) works: a few seconds after releasing the reset button the boot loop starts again.
Is there any other method to reset the device?
Thanks, Joachim.
Try netinstalling it
I tried this multiple times, also with different PCs - no luck, the device reboots while the reset-button is pressed.
Can the part of the firmware that handles this stage when booting get corrupted? If not, the reset button might have a mechanical/electrical problem, but the enclosure is not very service-friendly: Is it glued together at the side opposite the Ethernet-Ports?
For the records: Remove the tape opposite the eth ports, the enclosure can then be opened (the plastic noses are quite robust). I managed to get it into netboot mode by a short circuit over the reset button - it seems indeed to have a problem and does not consistently close its contacts when pressed.
https://www.dropbox.com/s/27akedo5nz3b57s/DSC_0445.jpg
Glad you found the fix!
Can the part of the firmware that handles this stage when booting get corrupted?
It can happen, you’d notice because after netinstall it won’t boot either, there’s a Backup Booter you can force on System > RouterBoard [Settings] in such case.