Dear Grandstream Customers,
Firmware 1.0.11.39 for GXP2130/2135/2140/2160/2170 is now released as official. Here is the link to the release notes:
http://firmware.grandstream.com/Release_Note_GXP21xxColor_1.0.11.39.pdf
The firmware and release notes can be downloaded from:
Please contact us should you have any issues. Thank you for your support for Grandstream products.
Technical Support
Grandstream Networks, Inc.
Very happy for new feature introduced with this release 1.0.11.39 (reboot after provisioning with P value P22421 set to 1. But… after setting P22421 to 1 our devices start an endless reboot, looping. Reboot, provisioning, registering… reboot, provisioning, registering. Impossible to stop the loop, the only way is re-set P22421 to 0.
Any suggestions? Phone are GXP2135 with firmware 1.0.11.39 (factory reset and re-provisioning doesn’t change).
honestly “P22241” I don’t think it exists on GXP213X etc …
Obviously the phone goes crazy, he must manage a non-eysider.
You’ll be confused with the GRP series.
Anyway, take the backup, delete “P22241” with notepad ++ and try to take it to the phone in TFTP.
If you don’t resolve you make a format factory, and then open a ticket here:
Hi Damiano. P22421 exist and it’s a new feature of firmware 1.0.11.39 for GXP21XX as you can see here at page 9
https://firmware.grandstream.com/Release_Note_GXP21xxColor_1.0.11.39.pdf
Ticket has been already opened but i am interested in a quick feedback if someone had the same problem with this new feature. I need it for a 2 stage provisioning in a large setup.
(p.s. in my inizial post i’ve made a mistake in writing the P Value)
Although I did copy paste, I searched for “P22241” error (which instead exists on GRP) 
Each mode test in TFTP as written above, or overwrite with zero config
All is right until i don’t use new P value 22421… so for me the problem is that function. Waiting for someone using this feature without having the same problem i’ve.