Unhappy Tate in "System Recovery" after trying Wallpaper Fix on 7.4.9

Hi,

I hope I can find some help. I have already searched this forum and some others but could not get a real picture what to do next (probably my Mac could be a problem here...)

I got a Kindle Tate (7" 2012) with 7.4.9.

I rooted it but did neither install a second bootloader nor a custom ROM. Only rooted and play store installed.

Today I tried to apply the wallpaper fix which changes the framework-res.apk file.
I looked at the shell script as my mac did not have the XML tool needed and so I replaced the value myself.

It seems now that the file got somehow corrupted and the Kindle is only booting to System recovery screen with red triangle now.
Of course the recovery does not help

I do not yet own a fastboot cable (unknown how to get one in Germany and I am not able to solder one - maybe the one on ebay.de stating for "Kindle Fire" could work)

On my Mac adb does not recognize the device and neither does fastboot (but ok I only got a standard cable)

What could I do next? At the moment I only got a windows running in VirtualBox which does not help as the Kindle is not recognized by the mac and can therefore not been forwarded to Win emulation.

Fastboot should as far as I understand also work from Mac if the device could boot there...