Can I2C2 be used for other purposes on Orin custom carrier?

[jhnlmn]

Hi,
Looking at Figure 13-1. I2C Connections in “Jetson AGX Orin Series Design Guide” it appears that all I2C are available for a custom carrier board except for I2C5, which is for On-module use only.
But when I tried reusing I2C2 for other purposes, I got kernel error
“Error: Sending messages failed: Input/output error”
and from tegrastats “ERROR: failed to read /sys/class/hwmon/hwmon1/in1_input”
Then I realized that I2C2 is connected to hwmon.
This is barely documented.
https://docs.nvidia.com/jetson/archives/r36.4/DeveloperGuide/SD/PlatformPowerAndPerformance/JetsonOrinNanoSeriesJetsonOrinNxSeriesAndJetsonAgxOrinSeries.html?highlight=ina3221#jetson-agx-orin-series
says:
“The Jetson AGX Orin series modules have two 3-channel INA3221 power monitors at I2C addresses 0x40 and 0x41” but it does not tell on which I2C bus it is.
The “Design Guide” does mention “Power Monitors (7H40 and 7h41)” on I2C2,
but it also mentions “ID EEPROM (7h50)” on I2C1.
I know that EEPROM is only present in DevKit and not on our board, so I do not have to worry about it.

But what about Power Monitors? Are they in DevKit or inside SOM?
I see some warnings that interfering with INA3221 can result in damage to the device.
Is it true?
This means that if I2C2 (J61 and K61) is connected to other resources on a custom carries board and those resources somehow block access to INA3221 (as often happens with I2C peripherals), then orin will burn?

Please, advise. Should we remove any external connectors from J61 and K61?
What other I2C are safe to use?

Thank you

[Trumany]

INA3221 is on module. I2C2 can be normally used as you can see there are many devices on carrier board are attached on I2C2.

[jhnlmn]

First, there is always a risk that one of I2C peripherals will intermittently jam one of I2C lines down, thus blocking the bus. This risk is higher if I2C bus extends via off-board cables.

Second, as I understand, Orin Pinmux spreadsheet allows to reconfigure I2C2 (J61 and K61) as GPIO, which will disable I2C completely. This is how I discovered this problem by accident: was changing J61 pinmux dynamically using “sudo busybox devmem 0x0c302030 w 0” and saw periodic “tegra-i2c c240000.i2c: I2C transfer timed out” messages by somebody.