Why manufacturer data's first two byte is always in reverse order?

[keval-devani]

Describe the bug When scanning BLE device only first two bytes in manufacturerData order is reverse.

To Reproduce Steps to reproduce the behavior:

1. set manufacturer Data in nrf connect for mobile
   • Company Identifier : 0059
   • Data : 5403202121.....
2. When Scanning in result device.manufacturerData give me data like this [89, 0, 84, 3, 32, 33, 33] that means 59 00

Expected behavior it should not reverse first two bytes in manufacturerData.

• I tried doing the same with a general BLE scanner application nrf connect and also try with flutter_ble lib that give me 00 59 in result

Smartphone / tablet

• Device: Moto moto one
• OS: Android 10
• Package version: flutter_reactive_ble: ^3.1.1+1

Peripheral device

• Vendor, model: nrf connect app for mobile (Poco F1)
• Does it run a custom firmware / software: no

Additional context

[jobfeikens]

Hi, its not in reverse.

From v4.2 of the spec:

2.4 Profile Fundamentals

    ...

    • Multi-octet fields within the GATT Profile shall be sent least significant octet first (little endian).

[werediver]

Thank you for looking into this, @jobfeikens.

I suppose, the above answer resolves the original issue.

[keval-devani]

But, what about v5? Is there is way to differentiate that it is coming from v5 or v4.2?

[werediver]

The same is true for BLE v5.0, see the Core spec p. 2225.

No, there is no (direct) way of determining the version of the BLE that your device supports.