Remove unneeded special features mode from documentation

README.org

@@ -165,38 +165,6 @@ Changing the coefficients will take effect only when the automatic mode is off.
 - Bit 1: music feature is activated
 - Bit 2: bootloader feature is activated
 
-** 0xFF Special features (R/W)
-
-Special features can be activated or deactivated by writing a
-variable-length byte sequence in one I²C write operation (this address
-does not auto-increment).
-
-- [C0 FF EE 01]: enter I²C bootloader (if enabled)
-- [FE FF 10 03]: reset the board (always enabled even after a failure)
-
-The following features can only be used 10 seconds after the board has
-been reset.  In case of a failed command, no other of those feature
-can be used until the next reset.
-
-- [AB 07 XX XX XX XX XX]: enable automatic motor mode
-- [BA 71 XX XX XX XX XX]: enable music feature
-- [90 70 XX XX XX XX XX]: enable bootloader
-
-=XX= values are chose at compile time and the board owner may chose
-not be publicize them. One value can be tested every 10 seconds at most,
-needing a mean time of ~174 years to randomly find the right value.
-
-**Note:** those could be dependent on the unique device ID in order to
-be able to selectively enable those features.
-
-The result of a command can be read as one byte at this address unless
-the feature executes an alternate firmware.
-
-- 0x00: success
-- 0x01: failure
-- 0x02: command executed too soon
-- 0x03: features locked because of previous failure
-
 
 * Bootloader command set