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Again: its just downloading the tool, start it -eventually with a ctrl/right-click as I cant sign it - and hitting the backup rom button.

Especially on Os below Yosemite as there is no system imtegrity policy to turn off.

On OpenCore driven systems s.i.p. for kexts is off, so no extra steps.

Otherwise its to turn off s.i.p. (temporarily). But thats common knowledge and sometimes needed for other tasks.

Easiest turn is to boot Mavericks if available and use it to make that firmware backup and analysing.
 
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