Some dell notebook family use a embedded controller based on 8051 cpu.
I don't know anything about software and reverse engineering but maybe some others can decipher what firmware inside controller do with hardware and with bios rom (which is somehow encrypted )
Hope you already know parameter -writekromfile to extract kbc or ec firmware.
Here I provide for inspiron 9400:
debug log from motherboard diagnostic connector from powering on to bootloader and then forced power off by button pressed
My question at this moment are:
-bios rom is loaded as one or have separate regions? (I'm able to run dell diagnostics without any partition on hdd so I think that is from bios,main block of data)
-last part of bios rom are something like bootblock which is loaded first? (I see some text strings related to 8051 and reflashing kbc)
-if I'm right what are real bios part?
-kbc initialize hardware and then load bios rom then bios rom deal then what code to execute from them or kbc access some code in bios rom?
in that case bios rom have this content -dell diagnostics,bios code,bootblock in that order.
-if kbc initialize hardware then bypass controll to bios rom can we use a larger spi flash and start another bios from start adress inside bios rom to use a non restricted bios
Hope somebody with better understanding microcontrollers can provide some more detailed info.
I also changed my boot logo then read bios dump and in some blank area appear a new region with NVRAM and some code inside but can.t find now where I saved,maybe this will help somehow.
And last thing. If needed I can sniff communications between kbc and bios chip if this is possible or capture debug data while doing some tasks.