3.7? why? Are you on DEX? one problem could be you tried to downgrade using a ofw. bad move. if what I tell you doesn't work you will have to use a flasher. OK TRY THIS...
download 999 downgrader
rename it and put it on a usb (/ps3/update/)
Unplug it. leave it unplugged for 2 minutes.
use your a/v cords not hdmi cord.
put in your usb flash with 9.99 downgrade in.
hold power down let console turn on and off.
release power. hold power down again til it beeps five times, let go of power.
IMMEDIATELY tap eject. you will be in a recovery mode.
do your firmware update. let it reboot and you should be fine.
In the future remember you can't downgrade with ofw. you have to use a cfw to get back on an 3.55 then ofw, then 3.55cfw and then your current cfw of choice. I am a firm believer in REBUG. I can easily go from any higher cfw to 3.55 and bypass a couple steps.
hope this helps.