Using Direct Sampling under 50 MHz tuning frequency

[waterwin]

Using RF Input, or Direct Sampling both work above 50 MHz.
RF Input :
make (0, 100500000.000000, 20000000.000000, 2, 7, 0, 0)
Fobos SDR API Info lib: 2.3.2 Feb 13 2025 14:03:23 drv: libusb
fobos_sdr_impl:: found devices: 1
open...ok
board info
hw_revision: 2.0.0
fw_version: unknown
manufacturer: RigExpert
product: Fobos SDR
serial: A1D610000007
(0, 100500000.000000, 20000000.000000, 2, 7, 0, 0)

Direct Sampling :
Direct Sampling
make (0, 50500000.000000, 50000000.000000, 2, 7, 1, 0)
Fobos SDR API Info lib: 2.3.2 Feb 13 2025 14:03:23 drv: libusb
fobos_sdr_impl:: found devices: 1
open...ok
board info
hw_revision: 2.0.0
fw_version: unknown
manufacturer: RigExpert
product: Fobos SDR
serial: A1D610000007
(0, 50500000.000000, 50000000.000000, 2, 7, 1, 0)

But not under 50 MHz. How can I reach the lower frequencies as advertised from 100 Hz to 25 MHz with the GNU Source block ?
make (0, 40000000.000000, 50000000.000000, 2, 7, 1, 0)
Fobos SDR API Info lib: 2.3.2 Feb 13 2025 14:03:23 drv: libusb
fobos_sdr_impl:: found devices: 1
open...ok
board info
hw_revision: 2.0.0
fw_version: unknown
manufacturer: RigExpert
product: Fobos SDR
serial: A1D610000007
(0, 40000000.000000, 50000000.000000, 2, 7, 1, 0)
fobos_rx_set_frequency - error!

And when will HF1 and HF2 be available, as non-IQ stream.

Thank you.