Bad ROM flash - Kindle Fire stuck in boot My KF won't finish booting.

I started to root my KF from my iMac using these instructions and with the files it points to.  I got as far as flashing it with FIREFIREFIRE which appeared to complete normally but at the fastboot reboot following, the device hung with its splash screen displayed ("kindle fire").  I waited 3 min and restarted it - same behavior.  I tried a hard reset and got the same behavior.  The KF has Android 2.3.4 and Kindle Fire 6.3.1.  A copy of the terminal output (with comments obviously inserted later):

jrobert@Gacrux platform-tools$ adb kill-server; adb devices
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
List of devices attached
1836002600000001    device

###  Neato - iMac sees the KF.
###  Into and out of the shell:

jrobert@Gacrux platform-tools$
jrobert@Gacrux platform-tools$ adb shell
$ ls
config
dropbox
cache
sdcard
acct
mnt
vendor
d
etc
ueventd.rc
ueventd.omap4430.rc
ueventd.goldfish.rc
system
sys
sbin
proc
init.rc
init.omap4430.rc
init.goldfish.rc
init
default.prop
data
root
dev
$ exit

### Push fbmode utility to KF and run it:

jrobert@Gacrux platform-tools$ adb push fbmode /data/local/fbmode
4976 KB/s (510876 bytes in 0.100s)
jrobert@Gacrux platform-tools$ adb shell chmod 755 /data/local/fbmode
jrobert@Gacrux platform-tools$ adb shell /data/local/fbmode
jrobert@Gacrux platform-tools$ adb reboot

### Flash the KF with FIREFIREFIRE:
jrobert@Gacrux platform-tools$ pwd
/Users/jeff/Downloads/Kindle/RootingTools/android-sdk-macosx/platform-tools
jrobert@Gacrux platform-tools$ fastboot -i 0x1949 boot u-boot.bin
creating boot image...
creating boot image - 210944 bytes
downloading 'boot.img'...
OKAY [  0.055s]
booting...
OKAY [  0.003s]
finished. total time: 0.059s
jrobert@Gacrux platform-tools$ fastboot reboot
&lt; waiting for device &gt;
^C

###  At this point, the KF hung, as the instructions said it might,
###  displaying its splash screen: "kindle fire".  After 3 minutes,
###  I forced a shut down and restarted it. It displayed the splash
###  screen and hung again.  I tried a hard reset - held the power
###  button down for 60 seconds, and restarted it.  Same behavior.

###  adb and fastboot get no response.
###  The power LED stays green.

jrobert@Gacrux platform-tools$ adb devices
List of devices attached

jrobert@Gacrux platform-tools$ fastboot reboot
&lt; waiting for device &gt;
^C
jrobert@Gacrux platform-tools$ adb shell /data/local/fbmode
error: device not found
jrobert@Gacrux platform-tools$ adb shell /data/local/fbmode
error: device not found
jrobert@Gacrux platform-tools$ adb devices
List of devices attached

jrobert@Gacrux platform-tools$ adb reboot
error: device not found
jrobert@Gacrux platform-tools$ adb kill-server; adb devices
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
List of devices attached

jrobert@Gacrux platform-tools$

###  Growl on the  iMac responds to my unplugging the USB while
###  the KF is powered up ("USB Disconnection  kindle").
###  Growl doesn't respond to my plugging in the KF's USB
###  with the KF powered up.
###  Growl responds to my powering the KF up or down with the
###  USB connected.  The KF file system does not get mounted.


adb and fastboot client get no response, and neither lists a device.  Growl on the iMac responds to my unplugging the USB while the KF is powered up ("USB Disconnection  kindle"). It doesn't respond to my plugging in the KF's USB with the KF powered up. Growl responds to my powering the KF up or down with the USB connected.  The KF file system does not get mounted on the iMac.

I can power it on and off with the power button (it requires a push-and-hold to shut down) and the power LED lights and goes out when I do.  I've tried push-and-holding the power button as soon as the LED lights; the unit shuts down after 10 seconds or so, just as in any forced shut-down.

I've ordered parts to make into a factory-cable and hoping I can recover it with that.  Is there anything else I can try in the meanwhile?
There are the two things of note that I see in your data:


The instructions indicate that you should use fastboot -i 0x1949 boot u-boot.bin. This is actually not correct, because the fastboot boot command is intended for hotbooting a boot.img, not a bootloader (they are different). The original XDA instructions give the proper command, which is fastboot -i 0x1949 flash bootloader u-boot.bin. This will install FIREFIREFIRE on your device, overwriting the stock bootloader.
Generally, if your KF hangs at the boot splash screen, it's stuck in fastboot mode. You can reset it to the normal boot mode by connecting it to a PC and executing fastboot -i 0x1949 oem idme bootmode 4000 and then rebooting. If you have FIREFIREFIRE installed you can leave off the -i 0x1949 flag because it uses a different vendor ID.