Procedure Mentioned below is applicable on all IOS versions above 11.3(1)MA1
Procedure:
1. go to enable mode
2. configure terminal
3. change register to 0x0
4. write to memory
5. reload will bring the router into rommon mode
6. type in "trunk E1" then hit Enter (trunk T1 if vise versa)
7. type "confreg 0x2102"
8. type "reset"
9. the router should reboot and change MFT trunk to E1.