[Q] Using fastboot -c topic

Hello everybody. I need help figuring out what command line configuration to put inside of the parentheses of

Code:

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fastboot -c "    "

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How can I find out what command line to put in so that I can use

Code:

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fastboot boot

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Apparently since Android 4.4 you can no longer simply do the commant

Code:

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fastboot boot img.mg

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and you have to do it something like

Code:

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fastboot -c "console=ttyHSL0,115200,n8 androidboot.hardware=mako lge.kcal=0|0|0|x" img.img

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or

Code:

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fastboot -c "lge.kcal=0|0|0|x" boot img.img

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or else it won't boot. The above commands work for the nexus 4. I do not have the source for my device but I do have the boot.img and zimage. My device is an Amazon Fire HD6. Thanks!