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From: Szymon Janc <szymon.janc@codecoup.pl>
To: Manuel Masiello <manuel@foobot.io>
Cc: linux-bluetooth@vger.kernel.org
Subject: Re: Bluetoothctl: "write" command only send one byte.
Date: Thu, 14 Jun 2018 00:54:17 +0200
Message-ID: <2575764.Np7OUyMvvF@ix>
In-Reply-To: <4043ca82-99c9-d1e9-37ec-3e484ad09250@foobot.io>
References: <4043ca82-99c9-d1e9-37ec-3e484ad09250@foobot.io>
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Sender: linux-bluetooth-owner@vger.kernel.org
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Hi,

On Thursday, 8 March 2018 18:11:26 CEST Manuel Masiello wrote:
> Hello everybody,
> 
> I write to the community because I have a problem using Bluetoothctl.
> I am looking to write in an attribute with the gatt command "Write".
> 
> Here is my command line operation suite:
> 
> $ bluetoothctl
> 
> [bluetooth]# power on
> [bluetooth]# connect A6:41:29:67:30:ED
> [my_device]# menu gatt
> [my_device]# select-attribute
> /org/bluez/hci0/dev_A6_41_29_67_30_ED/service0034/char0035
> [my_device:/service0034/char0035]# write 0x41 0x54 0x2b 0x4e 0x69 0x6d
> 0x70 0x00
> 
> This is where I have a problem. I never get an error message but the BLE
> device only receive the 1st byte 0x41.
> However, using Android applications like LightBlue or nRF Connect, it
> receives correctly what I seek sent.
> I scanned the net without finding an answer. I do not really understand
> why it does not work ...
> 
> 
> For information:
> Linux version 4.13.0-36-generic (buildd@lcy01-amd64-017) (gcc version
> 7.2.0 (Ubuntu 7.2.0-8ubuntu3.2)) #40-Ubuntu SMP Fri Feb 16 20:07:48 UTC 2018
> 
> I only have "Bluetoothctl" to do the job because the Alpine Linux
> distribution contains nothing else:
> https://pkgs.alpinelinux.org/contents?file=&path=&name=bluez&branch=edge&rep
> o=main&arch=x86
> 
> Is there anyone who can help me find my mistake?

Digging out this unanswered question as people seems to ask this on IRC too.
You need to use quotes:
write "0x41 0x54 0x2b 0x4e 0x69 0x6d 0x70 0x00"

And yeah, this could be fixed to accept also 0x01020304 and no quotes for 
conveniense:-)

-- 
pozdrawiam
Szymon Janc