It is not possible to extend the master database across another device, so the following from Eric McGrane (recently of Sybase Product Support Engineering) should help.

* dump the current master database

* Pre-12.5 users use buildmaster to create a new master device with a larger size. ASE 12.5 users use dataserver to build the new, larger, master database.

* start the server in single user mode using the new master device

* login to the server and execute the following tsql:

select * from sysdevices

* take note of the high value

* load the dump of the master you had just taken

* restart the server (as it will be shut down when master is done loading), again

in single user mode so that you can update system tables

* login to the server and update sysdevices setting high for master to the value

that you noted previously

* shut the server down and start it back up, but this time not in single user mode.