C2921 router will not bring up fibre SFP

Question

c2921 router will not bring up fibre SFP
I can't get two cisco 2921 routers to talk to each other
the setup works find in my testbed with a rj45 cross over cable between them or even with a WANEM cloud emulator(free tool).
after migrating from CU  to fibre they won't to talk to each other anymore. worse, both refuse to bring up their wan side fibre SFP.
the "media-type" sub i/f command was used to change to SFP from RJ45
after that, the EN SFP light appears on both routers, but no link light
sh int gi 0/1
GigabitEthernet0/1 is down, line protocol is down
  Hardware is CN Gigabit Ethernet, address is xxx(bia xxx)
  Description: ** TEST LINK
  Internet address is 1.1.1.2/30
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is SX
the two routers are in different buildings and must pass through a middle building(#2)
B1 - 200m -- B2 -- 900m -- b3
R1 (in building 1) is 200m from building 2
R2 (in building 3) is 900M from building 2
R1 has a MM SFP in Gi 0/1
R2 has a SM SFP in Gi 0/1 as the distance is too far for MM
in building two we have used both a SM to MM media converter
and a layer two switch with SM and MM SFP,
both show similar results
R1(MM sfp) --MM cable-- (MM sfp) switch (SM sfp) --SM cable--(SM sfp)R2
on the switch( in Bld 2), we see links lights coming out of the two routers, for both SM and MM links, this is good and expected. no traffic is seen though
on either router, no link light is seen and both interfaces are down down. shut, no shut, does not bring them up
we have tried different SFP and cables, still no change
one google search mentions an undocumented ciso command to ignore incompatibale SFP, but that does not work in IOS 15
if we add a 3750 switch to the routers Gi 0/1 WAN side as a media converter, we get success.
each switch has two sfp, one Cu and the other MM or SM fibre .
the router "media-type" sub i/f command was used to change to RJ45 from SFP, after that, the SFP EN lights goes out(as expected) on both routers,
R1(CU)-(CU)3750(MM sfp) --MMcable-- (MM sfp) switch (SM sfp) --SMcable--(SM sfp)-(SM sfp)3750(CU)R2
why does this work and the connection on the rtr does not
sh int gi 0/1
GigabitEthernet0/1 is up, line protocol is up
  Hardware is CN Gigabit Ethernet, address is xxx(bia xxx)
  Description: ** TEST LINK
  Internet address is 1.1.1.2/30
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is RJ45
this test is not practical in the deployed field and far too expensive
i am looking for a solution and want to know why the SFPs do not work in the routers
i tried two different MM SFP. neither one worked, though from SH INV, one can't tell them apart. on the CISCO site only this one is supported
glc-sx-mm, the SFP-GE-s is not supported on the 29xx rtr but is on the 3750 switch (;
================
%added SFP-GE-s SFP, the SFP-GE-s is not supported on the 29xx rtr but is on the 3750 switch
sh inv
NAME: "CISCO2921/K9 chassis", DESCR: "CISCO2921/K9 chassis"
PID: CISCO2921/K9      , VID: V03 , SN: xxxxSFP-GE-s
NAME: "1000BASE-SX SFP", DESCR: "1000BASE-SX SFP"
PID: FTLF8519P2BNL-C6B , VID: B  , SN: xxxx
%============
%remove SFP and added glc-sx-mm SFP, this is the supported MM SFPO for the 29xx rtr
sh  inv
NAME: "1000BASE-SX SFP", DESCR: "1000BASE-SX SFP"
PID: SFBR-5766PZ-CS1   , VID:    , SN: xxx
============
Cisco IOS Software, C2900 Software (C2900-UNIVERSALK9-M), Version 15.0(1)M3, RELEASE SOFTWARE (fc2) 
Cisco CISCO2921/K9 (revision 1.0) with 475136K/49152K bytes of memory.
Processor board ID xxx
9 FastEthernet interfaces
3 Gigabit Ethernet interfaces
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity enabled.
255K bytes of non-volatile configuration memory.
500472K bytes of ATA System CompactFlash 0 (Read/Write)
License Info:
License UDI:
Device#   PID                   SN
*0        CISCO2921/K9          xxx
Technology Package License Information for Module:'c2900'
Technology    Technology-package          Technology-package
              Current       Type          Next reboot
ipbase        ipbasek9      Permanent     ipbasek9
security      securityk9    Permanent     securityk9
uc            None          None          None
data          None          None          None
Configuration register is 0x2102

Answer 1

Problem solved.
MAJOR untested bug in IOS 15.0(1)M3 which was the default image when we bought the devices
*** AVOID IOS 15.0  series  ***
there are several bugs related to SFPs like:
does does recognize SFP
des not recognize some EHWIC cards such as, but not limited to EHWIC 1GE-SFP-CU
CSCtj35792  
c3900 : gigE SFP should switch to 1000/FD if other side has no nego
Externally found severe (Sev2) bug: M-More
CSCth28824  
c3945 GE shows DOWN/DOWN as compare to SFP
Externally found moderate (Sev3) bug: R-Resolved
They were fixed in 15.0(1)M4 or later
You can check the caveats for this IOS Release 15.0M:
http://www.cisco.com/en/US/docs/ios/15_0/release/notes/150MCAVS.html