"Length of data to send exceeds MTU" message on nrfConnect

RE: "Length of data to send exceeds MTU" message on nrfConnect

Simonr — Mon, 14 Jun 2021 13:07:11 GMT

This should not be an issue, this only means that the iOS DFU library will send the data in more than one transmission, and will not cause any problems for you.

Best regards,

Simon

RE: "Length of data to send exceeds MTU" message on nrfConnect

yayembedded — Fri, 11 Jun 2021 13:41:37 GMT

Hi Simon. Yes I know about the confirmation procedure. My concern is about the message that says, “Length of data to send exceeds MTU”. Sounds like there is something I should change.

Here are my prj.conf settings:

# Allow for large Bluetooth data packets.
CONFIG_BT_L2CAP_TX_MTU=252
CONFIG_BT_L2CAP_RX_MTU=252
CONFIG_BT_RX_BUF_LEN=260

I copied them from the ncs\v1.4.1\zephyr\samples\subsys\mgmt\mcumgr\smp_svr sample project.

RE: "Length of data to send exceeds MTU" message on nrfConnect

Simonr — Fri, 11 Jun 2021 09:47:39 GMT

Hi Christopher

Thank you, I discussed this with our nRFConnec for iOS developer, and this disconnect is normal. The DFU process waits for the device to restart to confirm a successful DFU. The line "State changed from test to reset" in the log tells you that it is now going to reset the device.

So there is nothing to be worried about in production.

Best regards,

Simon

RE: "Length of data to send exceeds MTU" message on nrfConnect

yayembedded — Wed, 09 Jun 2021 14:18:33 GMT

ios

RE: "Length of data to send exceeds MTU" message on nrfConnect

Simonr — Wed, 09 Jun 2021 09:22:21 GMT

Sorry, but this wasn't clear from the initial post, are you using nRFConnect for Desktop, nRFConnect for Android, or iOS?

Best regards,

Simon

RE: "Length of data to send exceeds MTU" message on nrfConnect

yayembedded — Tue, 08 Jun 2021 00:18:04 GMT

Please see below. Thanks.

---------------------------------------------------------------------------------------------------------------------------------------------------------

File Name: app_update.bin
Size: Zero KB
Firmware Upgrade Started.
State changed from none to validate
Central Manager ready
Connecting...
Peripheral connected
Discovering services...
Services discovered: 8D53DC1D-1DB7-4CD3-868B-8A527460AA84
Discovering characteristics...
Characteristics discovered: DA2E7828-FBCE-4E01-AE9E-261174997C48
Enabling notifications...
Notifications enabled
Device ready
State changed from validate to upload
Length of data to send exceeds MTU
Scanner Off.
State changed from upload to test
State changed from test to reset
Peripheral disconnected
[Callback] centralManager(central, didDisconnectPeripheral: peripheral, error: The connection has timed out unexpectedly.)
Disconnected.
State changed from reset to confirm
Connecting...
Peripheral connected
Discovering services...
Services discovered: 8D53DC1D-1DB7-4CD3-868B-8A527460AA84
Discovering characteristics...
Characteristics discovered: DA2E7828-FBCE-4E01-AE9E-261174997C48
Enabling notifications...
Notifications enabled
Device ready
State changed from confirm to success
Success!

RE: "Length of data to send exceeds MTU" message on nrfConnect

Simonr — Thu, 03 Jun 2021 08:27:59 GMT

Can you upload the log file so I can see what message the device is trying to send? That would help us get a better idea of what exactly is causing it.

Best regards,

Simon

RE: "Length of data to send exceeds MTU" message on nrfConnect

yayembedded — Wed, 02 Jun 2021 01:42:12 GMT

Hello, Simon. I missed the message earlier. The DFU is successful and the message happens before the update has completed. It occurs right after I press "begin" or "start" on the nrfConnect app

RE: "Length of data to send exceeds MTU" message on nrfConnect

Simonr — Wed, 26 May 2021 05:53:59 GMT

Can you provide the log from nRFConnect where this is stated? If the DFU is successful, when does this message occur, before or after the update has completed?

Best regards,

Simon