sgminer was hardcoded to report 300Mhz.
Its not picking up the value from STM board, what you see on sgminer interface is hardcoded string, nothing more.
I can make it report anything i want.
Moreover, Mhz setting to baikal_setoption is hardcoded as well, see below.
BL to_baikal_algorithm
LDRB.W R2, [SP,#0x70+fanspeed]
LDRB.W R3, [SP,#0x70+cutofftemp] ; temp
MOV.W R1, #0x12C ; ; set clock 300Mhz
STR R2, [SP,#0x70+var_70] ; fanspeed
UXTB R2, R0
MOV R0, baikal ; baikal
BL baikal_setoption
Changing supplied option to anything (over/undeclock) makes no difference in both calls to baikal_setoption.
I believe this setting is simply ignored by the STM firmware.
I changed that value to 0x190 in sgminer, but it didn't have any impact on the hash rate. So probably you are right.