Is there any way at all to the prerequisite stock firmware flashed without Windows? I don't have a Windows machine, just Mac OS X and Linux. I tried with a VMware XP machine, but the USB port isn't being properly forwarded to the virtual XP OS. I'm guessing because VMware only forwards recognized devices, and the mode my Fire goes in doesn't turn up as a USB device at all...
While definintely possible, flashing without SoC manufacturer's tool will most definitely be tricky to say the least. As for virtual machines, I used VirtualBox running on GNU/Linux with Windows XP as guest OS. I haven't used VMWare for years so I can't help with that.
I can't remember the exact details for the procedure, but here's roughly what I did. Proceed at your own risk.
- Turn off the device.
- Make sure USB cable is connected.
- Start watching kernel log, e.g. tail -f /var/log/kern.log
- Power the device holding the required keys pressed.
- Once Linux kernel sees the device (probably 1b8e:c003), enable forwarding this device to guest OS. Windows driver should now recognise the device and keep it in pre-boot environment. Device screen should remain black.
- Create a USB device filter so that the next time VirtualBox will enable the device automatically.
- Start the flash procedure.
- During the flash the Fire's USB device ID will change; watch kernel log, enable new devices and create filters for them. If it took too long to enable the device, flashing will time out and fail. Simply try again. You may have to press and hold power button to power off the device first.
- The last device to appear should be File-backed Storage Gadget. Once you get past this you should be about done and continue with flashing PA from rescue boot.
If your device is similar to mine, you can probably create the device filter prior to running the flasher. My device appears as three different devices (but with just two USB device IDs): 1b8e:c003 and 0525:a4a5, or Amlogic M3-CHIP, Amlogic M7-CHIP and Linux 3.0.8-g841cc85-dirty with dwc_otg_pcd File-backed Storage Gadget .