RGBS HDMI to VGA 240p on 15kHz CRT
https://www.instagram.com/p/CH1DZ0alyAr/SETTINGS ARE FOR RASPBERRY PI 3B+
Disable Monitor EDID
hdmi_ignore_edid=0xa5000080
hdmi_ignore_cec_init=1
Uncomment For TATE Mode (270 Degree)
#Display_lcd_rotate=3
Uncomment This If Your Display Has A Black Border Of Unused Pixels Visible And Your Display Can Output Without Overscan
#Disable_overscan=1
HDMI To VGA - DMT 640x480p@60hz
#Hdmi_group=2
#Hdmi_mode=4
HDMI To VGA 240p *Needs Sync Combiner, Set Width In LibRetro RetroArch 'Config' Cores To 640 - CEA 720x240p@60hz
hdmi_group=1
hdmi_mode=8
hdmi_pixel_encoding=4
Uncomment To Disable Rainbow Splash On Boot
disable_splash=1
boot_delay=1
Uncomment If You Get No Picture On HDMI For A Default "Safe" Mode
#Hdmi_safe=1
Uncomment The Following To Adjust Overscan. Use Positive Numbers If Console Goes Off Screen, And Negative If There Is Too Much Border
#Overscan_left=16
#Overscan_right=16
#Overscan_top=16
#Overscan_bottom=16
Uncomment To Force A Console Size. By Default It Will Be Display's Size Minus Overscan.
#Framebuffer_width=1280
#Framebuffer_height=720
Uncomment If Hdmi Display Is Not Detected And Composite Is Being Output
hdmi_force_hotplug=1
Uncomment To Force A HDMI Mode Rather Than DVI. This Can Make Audio Work In DMT (Computer Monitor) Modes
hdmi_drive=2
Uncomment To Increase Signal To HDMI, If You Have Interference, Blanking, Or No Display
config_hdmi_boost=5
Uncomment To Overclock The Pi2. 900 MHz Is The Default.
#Total_mem=1024
#Arm_freq=1000
#Gpu_freq=500
#Core_freq=500
#Sdram_freq=500
#Sdram_schmoo=0x02000020
#Over_voltage=2
#Sdram_over_voltage=2
Uncomment To Overclock The Pi3B. DO NOT USE FOR 3B+ 1200 MHz Is The Default.
#Total_mem=1024
#Arm_freq=1300
#Gpu_freq=500
#Core_freq=500
#Sdram_freq=500
#Sdram_schmoo=0x02000020
#Over_voltage=2
#Sdram_over_voltage=2
Uncomment To Overclock The Pi3B+. DO NOT USE FOR 3B 1400 Mhz Is The Default.
#Total_mem=1024
#Arm_freq=1425
#Core_freq=600
#V3d_freq=400
#Sdram_freq=550
#Over_voltage=1
#Temp_soft_limit=70
You Can Also Raise The Minimum Frequency Of The Dynamic Clock (Defaults Are 600 & 250 For Pi3B+)
#Arm_freq_min=900
#Core_freq_min=325
Uncomment Some Or All Of These To Enable The Optional Hardware Interfaces
#Dtparam=I2c_arm=On
#Dtparam=I2s=On
#Dtparam=Spi=On
Uncomment This To Enable The Lirc-Rpi Module
#Dtoverlay=Lirc-Rpi
Additional Overlays And Parameters Are Documented /Boot/Overlays/README
Enable Audio (Loads Snd_bcm2835)
dtparam=audio=on
gpu_mem_256=128
gpu_mem_512=256
gpu_mem_1024=256
#Overscan_scale=1
^ This is what I use with a Portta HDMI to VGA and a sync combiner
May also work with a HDMI to YPbPr!