867vae-k9 IOS after ios update then factory reset, cant login

[transmit1]

Router is Cisco 867vae-k9

Cisco CP Express was updated toverion 3.5 ok

IOS was c860vae-advsecurityk9-mz.151-4M5.bin

Factorry reset works aok and rests the password to the defaut

one-time cisco/cisco, (which works.)

Cisco CP web interfaces also ok, but gives message that some secutity features are not enable because of the old firmware.

So, then IOS was updated to c860vae-advsecurityk9-mz.157-3.M.bin

Then Factory reset

the  serial console, boots ok showing the new IOS version

and displaying Cisco CP onetime usename cisco/cisco message

but get 

% Login invalid

what can I do to get back in, I have tried factory reset several times.?

[transmit1 · Accepted solution]

I found the problem,
looks like the new IOs requires the factory reset button to be help for much longer than 10 sec.
I help it till ##################################
########################################### [OK]

and the default login was reste to cisco/cisco