Activate HDMI device is on

amosjerbi · April 25, 2025, 10:03pm

The following script allows you to activate HDMI in 1080P 60 hz.

Instructions:

Download the Script HDMI ON & Script HDMI off
Move the downloaded files to the /mnt/mmc/task folder.
Navigate to Apps > Task tooltip > HDMI on & off
Plug in HDMI cable and PROFIT!

The HDMI off will return to internal display, huge shout out to @bitter_bizarro and the command that returns to original resolution:

[ "$(GET_VAR "global" "settings/hdmi/enabled")" -eq 1 ] && SCREEN_TYPE="external" || SCREEN_TYPE="internal"
FB_SWITCH "$(GET_VAR "device" "screen/$SCREEN_TYPE/width")" "$(GET_VAR "device" "screen/$SCREEN_TYPE/height")" 32

Let me know how it works for you, cheers

amosjerbi · April 27, 2025, 5:47am

My git in case the other link expires: romnix/muOS_Basics/hdmi_on.muxzip at main · amosjerbi/romnix · GitHub

You could also extract the sh script of the zip and put in in tasks folder if you’d like to have it as a task.

amosjerbi · April 28, 2025, 8:38pm

Good news! Managed to reverse the HDMI back to internal dispaly AFTER you launched HDMI_on, just run HDMI_off.sh from task toolkit (the resolution will reset once you exit a rom you launched).

Install it on SD1/muos/task

github.com/amosjerbi/romnix

muOS_Basics/hdmi_off.sh

main

#!/bin/sh

# Source MustardOS functions
. /opt/muos/script/var/func.sh

# Disable HDMI first
DISPLAY_WRITE disp0 switch1 "0 0 0 0 0x4 0x201 0 0 0 8"
sleep 1

# Enable LCD interface
DISPLAY_WRITE lcd0 enable 1
sleep 1

# Set LCD as primary display with 480x320
DISPLAY_WRITE disp0 switch0 "1 480 320 60 0x4 0x201 0 0 0 8"
sleep 1

# Enable display
DISPLAY_WRITE disp0 enable 1

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github.com/amosjerbi/romnix

muOS_Basics/hdmi_on.sh

main

#!/bin/sh

# Source the common functions
. /opt/muos/script/var/func.sh

# Check current HDMI state
check_hdmi_state() {
    if [ -f "/tmp/hdmi_in_use" ]; then
        cat "/tmp/hdmi_in_use"
    else
        echo "0"
    fi
}

# Toggle HDMI state
toggle_hdmi() {
    current_state=$(check_hdmi_state)
    if [ "$current_state" = "0" ]; then
        # Turn HDMI on
        DISPLAY_WRITE disp0 switch1 "4 10 0 0 0x4 0x201 0 0 0 8" # Using 1080p (1920x1080) at 60Hz

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d0npian0 · May 8, 2025, 8:12am

Love this! Much better than having to reboot the device to go into HDMI.

Is it possible to make hdmi_off compatible with other devices, though? Using it on an RG35XX H makes the resolution of the device too big for the display and I need to reboot to get it back to normal.

Edit: maybe it could be dynamically adjusted by looking at the device info file in /root

xonglebongle · May 8, 2025, 11:32am

The ability to dynamically switch between the internal display and HDMI was removed due to widespread issues across various panel types of the H700 devices. In practice, hot-swapping displays triggered a range of faults from graphical corruption, incorrect colour rendering, blank output, and in severe cases, a rainbow screen crash requiring a full hard reboot.

This wasn’t a removal for the sake of limitation. It was a measured decision to improve system reliability. Having the ability to switch HDMI on boot ensures predictable behaviour and provides a stable baseline for future implementation.

While it is technically possible to re-enable dynamic switching, as shown in the original post, doing so is at your own discretion and may result in system instability or hardware lockups.

d0npian0 · May 8, 2025, 3:42pm

I see, thanks for clarifying it! Maybe there could be an option to enable switching dynamically when it detects an HDMI cable, just have it disabled by default and maybe with some kind of warning. I get that it’s safer to reboot into it, but I’d be willing to take the risk!