Boot time Optimisation in Orin-Nx

[anakha.s]

Hi Team,

We are using a custom board based on the Jetson Orin NX module, running JetPack 6.2, which includes Jetson Linux 36.4.3 (Kernel 5.15) and an Ubuntu 22.04 root file system.

Our current focus is on reducing the boot time, and for that we tried

• Disable MB1/MB2 Logs
• Modify combined uart
• Pass “quiet” to kernel cmdline
  But no significant change in boot time
  Current time
  systemd-analyze
  Startup finished in 8.694s (kernel) + 15.733s (userspace) = 24.428s
  graphical.target reached after 15.702s in userspace

we would appreciate any guidance or recommendations you can provide to help achieve this.

[KevinFFF]

Hi anakha.s,

@anakha.s

Modify combined uart

What’s “Modify combined uart”? Could you share the details about this?

UEFI takes long time to boot. I think you can optimize the boot time in UEFI first.
Please share the full serial console log with timestamp enabled.

[anakha.s]

For modification made in the combined UART i referred the NVIDIA doc

Full console log with timestamp
full_serial_console.log (134.1 KB)

[anakha.s]

applied changes patch

git diff .
diff --git a/Linux_for_Tegra/bootloader/l4t_initrd.img b/Linux_for_Tegra/bootloader/l4t_initrd.img
index bd610a144..96413d41f 100644
Binary files a/Linux_for_Tegra/bootloader/l4t_initrd.img and b/Linux_for_Tegra/bootloader/l4t_initrd.img differ
diff --git a/Linux_for_Tegra/bootloader/tegra234-mb1-bct-misc-common.dtsi b/Linux_for_Tegra/bootloader/tegra234-mb1-bct-misc-common.dtsi
index 32ead8270..e81f40357 100644
— a/Linux_for_Tegra/bootloader/tegra234-mb1-bct-misc-common.dtsi
+++ b/Linux_for_Tegra/bootloader/tegra234-mb1-bct-misc-common.dtsi
@@ -183,7 +183,7 @@
#ifdef DISABLE_UART_MB1_MB2
log_level = <0>;
#else

•        log_level = <4>;
  

•        log_level = <0>;
  

endif
uart8_usb_port_sel = <0>;
usb2_nvjtag = <0>;

diff --git a/Linux_for_Tegra/p3767.conf.common b/Linux_for_Tegra/p3767.conf.common
index d5c69fd3e..0ad87f78c 100644
— a/Linux_for_Tegra/p3767.conf.common
+++ b/Linux_for_Tegra/p3767.conf.common
@@ -145,7 +145,7 @@ ODMDATA=“gbe-uphy-config-9,hsstp-lane-map-3,hsio-uphy-config-0”;
CHIPID=0x23;
ITS_FILE=;
OVERLAY_DTB_FILE=“L4TConfiguration.dtbo,tegra234-carveouts.dtbo,tegra-optee.dtbo”;
-CMDLINE_ADD=“mminit_loglevel=4 console=ttyTCU0,115200 firmware_class.path=/etc/firmware fbcon=map:0 nospectre_bhb video=efifb:off console=tty0”
+CMDLINE_ADD=“mminit_loglevel=1 console=ttyTCU0,115200 firmware_class.path=/etc/firmware fbcon=map:0 nospectre_bhb video=efifb:off console=tty0 quiet”
target_board=“generic”;

[KevinFFF]

@anakha.s

full_serial_console.log (134.1 KB)

From the log you shared, it takes 45s for boot up from MB1 to linux log-in.

@anakha.s

applied changes patch

Could you also share the full serial console log with timestamp enabled after you’ve applied these changes?
I would expect there’s no MB1/MB2 logs and the logs from kernel should be decreased significantly.

[anakha.s]

changes_appliedbootlog.txt (32.1 KB)
Attaching boot log after applying the changes
Could you please suggest some recommended methods to reduce boot time on JetPack 6.2?

[KevinFFF]

It seems you’ve disabled MB1/MB2 logs successfully.
There’re about 20s in UEFI as following, I think you can optimize the boot time from here.

[2025-07-10 09:31:00.121] Jetson UEFI firmware (version 36.4.3-gcid-38968081 built on 2025-01-08T01:18:20+00:00)
...
[2025-07-10 09:31:21.941] ��I/TC: Reserved shared memory is disabled

Please refer to miniUEFI Support and 最近我移植比较新的固件jetson36.4.3，发现UEFI开机时间太长，UEFI启动我花了40秒才到UEFI logo界面。 - #21 by KevinFFF to use miniUEFI to optimize the boot time of UEFI.