Is mentioned in wiki for the "fantbl" command but this rule seems to apply to 5 commands in total (fanconpolicy, fantbl, hyst, trp, and tshutdown)
The "get/set" subcommands applyes the commands in syscon RAM, so are volatile, only applyes to the current session
And the "getini/setini" applyes the changes in EEPROM permanently
I guess this is related with how the syscon loads the data from the EEPROM, at some early point of the syscon boot sequence it copyes the contents of the syscon EEPROM to syscon RAM... and then it uses the data from syscon RAM (in other words, the real data from EEPROM is not used on runtime)
Lets say... when they was configuring it they was using the "get/set" subcommands more frequently to make tests on runtime
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That "pre-boot spin-up" you refer is the value named "initial_fan_duty" (with a time lenght of "initial_fan_time")
Is represented in my graphs with the horizontal lines dotted at left, because i could not figure any better way to represent it, is tricky because the graph doesnt represents time... when looking at my graphs you can imagine that transition in between the dotted lines have a lenght of 2 seconds
All the PS3 models equal or older than CECH-20xx (or so, i dont have samples of the thermal config of CECH-21xx/SUR-001 motherboards yet, so im not sure exactly when it happened) uses an "initial_fan_duty" of 30% fan speed, and after a couple of seconds (indicated by the value of "initial_fan_time") decreases to the speed indicated in the step named "P0" in the fantables (that seems to be always 20% fan speed for all the PS3 models)
And the PS3 models equal or newer than CECH-21xx works in the same way, the only difference is the "initial_fan_duty" is 25% fan speed instead of 30%
Edit:
Think in it this way... the fan speed values from inside the tables are dependant of the value of the thermal sensors (if the temperature of the sensor varies then the fan speed varies)
But in the first 2 seconds when we boot the PS3 the syscon is keeping the fan speed "locked" to the "initial_fan_duty" that is not dependant of the thermal sensors
Lets say... in the first 2 seconds syscon is controlling the fan in a "brainless" way and is ignoring the thermal sensors