Open-Q 820 HDMI support with 5.10.0-qcomlt

I have Open-Q 820 Dev Kit from Intrinsyc which I’ve flashed with

It does not detect display connected to HDMI
cat /sys/class/drm/card0-HDMI-A-1

Boot log doesn’t show much issues

[ 30.542112] msm 900000.mdss: supply vdd not found, using dummy regulator
[ 30.549392] Bluetooth: HCI UART protocol LL registered
[ 30.552943] msm_mdp 901000.mdp: [drm:mdp5_bind [msm]] MDP5 version v1.7
[ 30.555802] Bluetooth: HCI UART protocol Three-wire (H5) registered
[ 30.559695] msm 900000.mdss: bound 901000.mdp (ops mdp5_ops [msm])
[ 30.611929] Bluetooth: HCI UART protocol Broadcom registered
[ 30.612225] Bluetooth: HCI UART protocol QCA registered
[ 30.619220] Bluetooth: hci0: setting up ROME/QCA6390
[ 30.632004] msm 900000.mdss: bound 9a0000.hdmi-tx (ops msm_hdmi_ops [msm])
[ 30.633763] adreno b00000.gpu: supply vdd not found, using dummy regulator
[ 30.685646] adreno b00000.gpu: supply vddcx not found, using dummy regulator
[ 30.696854] msm 900000.mdss: bound b00000.gpu (ops a3xx_ops [msm])
[ 30.777140] ath10k_pci 0000:01:00.0: enabling device (0000 -> 0002)
[ 30.777833] ath10k_pci 0000:01:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 reset_mode 0
[ 30.892573] [drm] Initialized msm 1.6.0 20130625 for 900000.mdss on minor 0
[ 30.893731] msm 900000.mdss: [drm:adreno_request_fw [msm]] loaded qcom/a530_pm4.fw from new location
[ 30.917369] msm 900000.mdss: [drm:adreno_request_fw [msm]] loaded qcom/a530_pfp.fw from new location
[ 30.918504] msm 900000.mdss: [drm:adreno_request_fw [msm]] loaded qcom/a530v3_gpmu.fw2 from new location

I’ve enabled display in fastboot
fastboot oem select-display-panel hdmi

In this case I could see linux logo on the screen but than board gets reboot and than just hangs.
I know there are some issues with splash screen

Is there any additional debugging available to make it work?