The B10B and B10C use the same firmware files, and presumably share the same bugs.
Loss of Static Routes
Saved Static Routes aren't automatically reapplied after a power cycle.
After a power cycle: Login to router, select Network Setting, Routing. Modify, Edit static routes(s) to disable, then Modify, Edit static route(s) to enable.
?? Present in firmware versions up to and including AAVF.12
Loss of default IPv6 route on WAN
Brief (~60 second) WAN outages can cause the router to lose its default IPv6 route (e.g. DLM resets, LNS switchovers). The router no longer listens for Router Advertisements on its PPP interface, and so never relearns its default IPv6 route.
If you have cracked the supervisor password, then the same password is used for the root account. Log in over telnet or ssh as root, and issue the command:
echo 1 > /proc/sys/net/ipv6/conf/ppp1.3/accept_ra
It will take up to ~1 hour to receive a Router Advertisement and restore the default route.
If you haven't cracked the password, you could manually add a static route (as a quick and dirty solution). Valid gateway addresses are
fe80::203:97ff:fe05:c000 fe80::203:97ff:fe19:8000 fe80::203:97ff:fe44:4000
Or you could just power cycle the router...
Looks to be fixed in AAVF.12