purpose of passing this information to an OS kernel we are about
to boot
+Correct flow of setting up the MAC address (summarized):
+
+1. Read from hardware in initialize() function
+2. Read from environment in net/eth.c after initialize()
+3. Give priority to the value in the environment if a conflict
+4. Program the address into hardware if the following conditions are met:
+ a) The relevant driver has a 'write_addr' function
+ b) The user hasn't set an 'ethmacskip' environment variable
+ c) The address is valid (unicast, not all-zeros)
+
+Previous behavior had the MAC address always being programmed into hardware
+in the device's init() function.
+
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Usage
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