Set Image to boot from 2 images in flash

hi,
I recently upgraded the image in a 1841 router, the memory in the flash was adequate enough to hold the older image and the upgraded image.
On setting on the configuration file; boot system flash flash:xxxx upgraded image xxxxx, and saved the configuration.
On reloading the the router, during booting it still loads the older image and on doing a show version; the router displays the older image too.
I have tried a couple of suggestions from the internet research e.g using the set variable on rommon mode but unsuccesfully;

Anyone with an idea to resolve this ASAP would kindly appreciate as its a router in production and need to add some additional 3g HWIC card for a fail-over

Are the images in the same directory in Flash? If not, make sure you're pointing the boot system flash command at the specific location (i.e.: boot system flash:<directory><image.bin>)

Thanks KILLaBeE,
the images are on the same flash n directory.

I had pointed the correct image from the boot system flash in the startup-config.

I figured out that in the directory of the flash, the first image listed is always one that will boot first;

this is by setting the boot variable:

so I had to change and set the required image to be the first in the flash slot1.

Router# show run | include boot
boot system slot1:c3640-i-mz.120-22.bin

Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#no boot system
Router(config)#boot system slot1:c3640-i-mz.122-7b.bin
Router(config)#^Z
Router#wr memory

the above sets the new image as the default boot