About half a month ago we discussed how to simulate NVRAM on Hackintosh, especially for those PC without UEFI support. Let’s figure out a little more about NVRAM.
As for NVRAM module, lots of data are stored there:
These are NVRAM data on my Hackintosh (BIOS+GPT+Clover). Among those variables, we may focus on some specific ones like:
backlight-level —- save current backlight value data.
fmm-computer-name/fmm-mobileme-token-FMM —- save current “Find My Mac” status (enable or disable).
If the NVRAM are not saved before system shutdown and not properly set during startup, these data will lost and lead to the backlight level reset to its default value and disable the “Find My Mac” function. That’s exactly what I talked about in my earlier blog.
But sometimes we may find that we lost those values again, which means one day your backlight level is reset and FMM state is disabled after every startup. Meanwhile, the shutdown script and startup plist are all untouched. In this situation, resetting NVRAM can always work ’cause one or more NVRAM variables contain incorrect value or cannot be handled properly due to lack of Apple UEFI support.
For Hackintosh, resetting NVRAM would be easier as that on real Macs. Just type this in Terminal to delete all NVRAM data:
# nvram -c
Or just delete certain variable(s) if you know which one of them causes problem.
# nvram -d efi-boot-device-data
After clean up or fix the NVRAM, we can try adjust backlight level and recheck the FMM status. Now restart the OS X, everything should works fine.