Need Technical Support on - BNO055 - Difference between silk print A6 and A9

[Sugary]

Need Technical Support on -  BNO055 - Difference between silk print A6 and A9

One of our productS has been using one of your components since last year.

Part Number : BNO055

Description: Intelligent 9-axis absolute orientation sensor.

However, we encountered some problems recently when we were using this BNO055 senero.

We were ordering/using as below before, it worked as expected.

Silk print:
701
A9
LRY 

However, the last batch we ordered didn't work as we expectation.After deeper investigation, we found the silk print differs from the ones we ordered before.

Silk print:
701
A6
LRY

We checked the datasheet, we found the 2nd line from your datasheet shows this is for your internal use purpose.

I contact you immediately and want to get your support on below points :

1>. What's the difference between A9 and A6? Are they compatible with each other?

2>.If A6 isn't compatible with A9, what's the best solution for us to correct the problem? (we found the A6 sensor doesn't work)

3>. Or maybe we ordered a wrong sensor or a fake sensor?

Looking forward to support and Thank you very much!

[Sugary]

And from the dtasheet, it seems either A6 or A9 are the same function, just different batch or internal use. But what's th difference?

[BSTRobin]

Hello Sugary,

The second row marking was internally used.
Could we know information from you:
1.Where you bought BNO055?
2.For "However, the last batch we ordered didn't work as we expectation.", could you describe first what is the specific phenomenon that it can't work?

[Sugary]

Thanks for your reply.

We ordered 501PCs in May-2021 at very high unit price from a local web shop (www.icsuns.com)
We contacted with them for the issues already, but they 
The silk screen of the chip we received is A6, not A9, We already contacted them for this problem.
but they now claim that the silk screen of the chip sold to us is A9, not A6.
If you can help us recover the payment, we would be very grateful.

For the detailed pehnomonon is the IMU doesn't work at all, all 500PCs not work!
After change A6 chip to A9, then the board can work normally.

Below reports is from my colleagues:

After i further focused on the i2c communication between the uC and the imu, i figured the following:
- The Chip(BNO055) isn't responding to its I2C Address (0x28), nor to its second Address (0x29), screenshots attached.
- The I2C Bus voltage levels are correct and the pullup resistor values are also fine
- I2C timings / frequencies are identical to the ones from the last working batch of pcbas (measured / compared them).
- After probing through the whole address range i figured that the bno055 is responding to i2c address (0x48), also able to reliably read some register values then.
Which is kind wierd, because this address isn't listed in any of the documentation. But maybe i'm missing smt. here.
- Unfortunately i'm not able to check the solder joints of this bga chip, as they're right below the chip.

We definitly need to get this sorted quickly, as we currently aren't able to use these pcbas. 

Thank you very much again.

[Sugary]

Can I say the BNO055 Chips we ordered with A6 silk print are fake chips?