Command to change boot image of cisco 4506 router

Hello Experts,

I am looking for the appropriate command(s) for switching the boot image on a Cisco 4506E with a Sup6E.  I have successfully tftpd the new image to the router but all efforts to boot from the new image have failed.  I used the following commands:

Switch(config)#no boot system flash bootflash:cat4500e-entservices-mz.122-40.SG.bin
Switch(config)#boot system flash bootflash:cat4500e-ipbasek9-mz.122-50.SG1.bin

Here are the outputs from the show bootflash and bootvar commands:

LAX-LAN_AH37-WS-C4506-E#sh bootflash
-#- --length-- -----date/time------ path
 1     18119527 Jun 14 2008 08:07:44 cat4500e-entservices-mz.122-40.SG.bin
 2     21976060 Feb 24 2009 14:20:18 cat4500e-ipbasek9-mz.122-50.SG1.bin
85995520 bytes available (45441024 bytes used)

LAX-LAN_AH37-WS-C4506-E#sh bootvar
BOOT variable = bootflash:cat4000-i9k91s-mz.122-25.EWA14.bin,1;flash:/cat4500e-ipbasek9-mz.122-50.SG1.bin,12;bootflash:/cat4500e-ipbasek9-mz.122-50.SG1.bin,12;bootflash:cat4500e-ipbasek9-mz.122-50.SG1.bin,1;
CONFIG_FILE variable does not exist
BOOTLDR variable does not exist
Configuration register is 0x101

I have done this a hundred times on our managed switches but the commands on the router are slightly different and I cant seem to find the correct syntax.

 

Any advice?