We have a C6509E with dual VS-SUP2T-10G running 15.0(1)SY6. A WS-X6904-40G-2T module is in slot1 and 2. They have CVR-CFP-4SFP10G converters in the slots. The GLC-SX-MMD 1Gbps optical transceivers are not recognized, even though they are on the supported list.
I have 15.1(2)SY4a and don't see an option to change hw-module operational mode to 1G, only from 40G to TenGig, looks like the switch sees the 1G SFP (show interf transceiver) though. Does anyone else have the same problem?