Cant get "USB downloader mode" to replace Firmware Kindle Keyboard 3 B008 -

I have purchased a SH Kindle Keyboard Kindle 3 B0008 and wish to revert the firmware and jailbreak.
Currently it has 3.4.2

I am unable to get the device into what is referred to as 'USB downloader mode'.

I have followed several instructions and none seem to yield the desired results.
Could someone please advise:
1. What should appear on the screen in "USB downloader mode"?
2. Is it essential that device is connected with USB to initiate this?
3. The exact procedure to engage this mode
4. What should somewhere be replaced with in "./k3flasher /some/where/mx35to2_mmc.bin info"
5. Is mx35to2_mmc.bin a file that should be downloaded from somewhere?

I run Ubuntu and have tried
1. Connect your Kindle via USB to the computer. Hold the power button for 30 seconds and then without letting go, press and hold the vol - button for 1 second, then release only the power button, wait 1 second, then release the volume button.... from https://wiki.mobileread.com/wiki/K3noobdebrickatk

and

2. from the README of k3flasher
Now make a physical USB connection to your device and do the reset.
Remember to keep the Vol- button pressed during reset.

If your device's system is actually up and running, the preferred way to
do a reset is by going through Menu -> Settings -> Menu -> Restart.

3. If your device's system is bricked, hold Vol- and then shift and hold the
power slider for at least 15 seconds. Then release the slider and keep
the Vol- button pressed. After a maximum of 15 seconds, k3flasher should
recognize the device.

I noticed one guide also mentioned using the vol + button which I have tried also.

With all attempts the most I can get is a drive mounted from the kindle in linux, and no combination of k3flasher seems to detect the device.

Please help me get this organised.

Thankyou

Jesse