I am trying to configure a hotspot, using radius to authenticate, with multiple DHCP pools (a public and a private IP pool).

To do this, I am using the "framed-pool" radius attribute to define what pool the user is assigned to.

However, when the routeros receives the radius accept with the framed-pool attribute, it locks up hard. Will not respond to ping or telnet or winbox; has to be powercycled.

Has anybody else experienced this issue?

I've tried monitoring the log, but the box locks up before anything can be written to it.

Sorry it took a while to post an answer. Had to test it first. No problems here. There are a couple rules to follow to get it to work.
1) assign multiple IP pools within the IP netmask of the hotspot gateway.
2) Framed-Pool must be the name of the pool used on the MT router.

I used
hotspot IP/netmask 192.168.0.1/24
dhcp-pool1 192.168.0.32-192.168.0.250
dhcp-pool3 192.168.0.4-192.168.0.31
...and in the RADIUS server radreply table, I set user "SurferTim" attribute "Framed-Pool" value "dhcp-pool3".
It issued 192.168.0.250 on connection, and was changed to 192.168.0.31 on login. However, this is only the one-to-one NAT IP in "/ip hotspot host". The computer I logged in with remains set to 192.168.0.250, and the hotspot NATs it to 192.168.0.31.