Raspberry Pi 1B: usercfg.txt does not seem to have any effect
I installed Alpine Linux 3.16.1 on a Raspberry Pi 1B using the wiki (https://wiki.alpinelinux.org/wiki/Raspberry_Pi). All works fine, except the CPU is locked to 700Mhz and runs quite hot. The CPU settings are untouched by me. The governor is set to powersave out of the box. This is fine by me, but unfortunately there is only 1 frequency available:
pi:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
powersave
pi:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
700000
which happens to be the max of my device. Using vcgetcmd I can query the active settings:
pi:~# /opt/vc/bin/vcgencmd get_config int
aphy_params_current=547
arm_freq_min=700
audio_pwm_mode=514
camera_auto_detect=-1
config_hdmi_boost=2
disable_auto_turbo=1
disable_commandline_tags=2
display_hdmi_rotate=-1
display_lcd_rotate=-1
dphy_params_current=547
dvfs=3
enable_tvout=1
enable_uart=1
force_pwm_open=1
framebuffer_ignore_alpha=1
framebuffer_swap=1
ignore_lcd=1
init_uart_clock=0x2dc6c00
max_framebuffers=-1
pause_burst_frames=1
program_serial_random=1
ramfsaddr=-1
total_mem=512
hdmi_force_cec_address:0=65535
hdmi_force_cec_address:1=65535
hdmi_pixel_freq_limit:0=0x9a7ec80
As can be seen, the minimum frequency is set to 700. Using usercfg.txt this should be changeable, so I created /media/mmcblk0p1/usercfg.txt with the following content:
pi:~# cat /media/mmcblk0p1/usercfg.txt
arm_freq_min=250
arm_freq=700
force_turbo=0
But this is entirely ignored it seems, as none of these settings are present in the vcgencmd output after reboot. What do I have to do to have the usercfg.txt loaded?