"No HDMI Signal Detected" after a warm reboot

[freeyoung]

Disclaimer

• I have read and understood the disclaimer.

Application version

0.4.9-dev202510091414

System version

0.2.6

Device model

JetKVM

Extension model

None

Remote device Hardware

AsRock Z270m ITX/ac

Remote device OS

Debian 13

Bug description

The HDMI signal gets lost after a warm reboot in the running OS (a reboot command, or Ctrl + Alt + Del), and does not come back automatically, until I refresh the whole page - then "Loading video stream" starts and the display is back.

A cold boot seems to be NOT affected.

[zandercodes]

Which browser do you use?

[freeyoung]

Which browser do you use?

Hi, thanks for your reply! I'm using Chrome (Version 141.0.7390.66 (Official Build) (arm64))

[zandercodes]

I think it might have something to do with the CGO migration from jet_native, possibly. #635

You could try changing the display ID. That might fix the problem.
Does this problem also occur with other operating systems such as Windows on the same device?

[freeyoung]

You could try changing the display ID. That might fix the problem.

Changing the EDID won't fix the issue or work as a stable workaround. From what I saw, it was equal to refreshing the whole page.

Meanwhile I have a trick to avoid refreshing the whole page or changing the EDID, because my assumption was that the issue was related to the HDMI sleep mode (#881).

echo 0 > /sys/devices/platform/ff470000.i2c/i2c-4/4-000f/sleep_mode

Does this problem also occur with other operating systems such as Windows on the same device?

Yes, it's reproducible regardless of OS or device. I tried with a Lenovo P340 Tiny and the same issue occurred 100%.

[ashcoding]

Similar issue. My HDMI image is frozen instead. I use https://app.jetkvm.com/ to access my KVM.
IT's running version: 0.4.9-dev202510091414

After a reboot, the HDMI won't comeback.

After switching EDID screen types, the HDMI won't comeback.

Also, sometimes when I login the first time, the HDMI is frozen (but the keyboard and mouse works) but the Video is frozen.

I can reproduce it easily too.

[joosttromp]

I have the exact same issue. Just after a warm reboot, the keyboard still works but HDMI keeps saying not connected, it does not return after the reboot and I need to re-login to JetKVM to get hdmi signal.

App: 0.4.9-dev202510091414
System: 0.2.6

For example, if I keep pressing F2 after a reboot, the display does not return, but if I log out of JetKVM and log back in again, the system has actually entered the bios. This behavior is the same for local access, as well as cloud access. This is also not exclusive to entering the bios. I always need to re-login to the JetKVM to get 'HDMI Signal' back.

I remember this was working correctly earlier (I don't recall exact firmware versions).

Have changed display EDID's to acer / asus and this didn't solve anything.
Have set the primary display to HDMI1 in the bios (that's where JetKVM is connected), I have set any other virtual display emulation in the bios to off.
And I have intel-AMT access to verify / recover from any unexpected behaviour. But I want to rely on JetKVM externally, not intel-AMT, that I only use on LAN.

[adolfotregosa]

Me too. HDMI was rock solid. Now it's either not coming back or I constantly need to refresh the browser.

App: 0.4.9-dev202510091414
System: 0.2.6

[zandercodes]

What I'm wondering right now is why you're using an unstable dev version and not the stable release 0.4.8?
I don't have this problem in version 0.4.8. And I can confirm that it is related to the Dev version.

[joosttromp]

for some reason I've tried the developer mode and dev channel updates, don't remember why.
How'd I flash it back to 0.4.8?
unticking dev updates and checking for firmware updates doesn't offer me to downgrade.

[adolfotregosa]

for some reason I've tried the developer mode and dev channel updates, don't remember why. How'd I flash it back to 0.4.8? unticking dev updates and checking for firmware updates doesn't offer me to downgrade.

Afaik you have to dfu reinstall firmware

[joosttromp]

I've ran these lines in SSH and hoped to be able to upgrade back to 0.4.8. but now, the webinterface is down.

export JETKVM_UPDATE_TMPFILE=$(mktemp) && \
wget -c http://update.jetkvm.com/app/0.4.6/jetkvm_app -O $JETKVM_UPDATE_TMPFILE && \
sha256sum $JETKVM_UPDATE_TMPFILE | grep 05c6930cc1202196515f3aef06b94add7207e13d0b5e09da05dc5302ed5a0650 && \
chmod +x $JETKVM_UPDATE_TMPFILE && mv $JETKVM_UPDATE_TMPFILE /userdata/jetkvm/jetkvm_app.update && reboot

EDIT: okay yes, DFU is next

[luckman212]

where are the instructions for DFU downgrade- I am also plagued by this HDMI issue and want to flash back

[joosttromp]

where are the instructions for DFU downgrade- I am also plagued by this HDMI issue and want to flash back

https://youtu.be/bdHUMB3Kyig?si=_gyQ_ROM0pwVwg2E

On the Luckfox page are also instructions for linux, using upgrade_tool. use the update.img from jetkvm, that’s what I did and worked. as soon as jetkvm boots in DFU, it registers as some rockchip USB device and it can be flashed. The update.img is v0.4.5 but updates in web interface 0.4.8