how can I change the i2c bus frequency from 400kHz to 100kHz?

Hello,
On an Up Board Squared Pro 7000 (upn adlni3 a10 1664) with BIOS version UNADAM28 01/01/2024 (updated by myself), I'm trying to force an i2c bus to 100 kHz.
I've tried to change it in the bios but there are no parameters to do so in HAT PIN configuration. So I updated the bios and it's the same thing, there are no parameters to change. I've added i2c_dw.force_bus_speed=100000 in the kernel command line, but the frequency remains at 300 kHz (confirmed on the oscilloscope). Is there any other way to change this frequency?
Thank you for your help.