In the device parameter access example you actually change the modem name in the example (aleos.mdm.modem_name). This parameter does not feature part of the ‘device variable tree’ list in the tutorial and yet it is used in the example. So I guess being able to write over aleos parameters is not something you want to let the beta customers do, however is there a list of other parameters that i can write over? 
Hello,
Re aleos.mdm.modem_name: indeed this is an undocumented parameter. During Beta development we exposed a few items to the device tree that in the end thought might be confusing or misleading to customers and decided to not document. mdm.modem name is one of those. I will make a note to update the sample app so that it uses only publicly exposed items, thanks for bringing this to our attention.
Re write-able items: right now the values exposed in the device tree are all read-only. We will be sure that the documentation expose read/write capabilities of each item.
Regards,
-Kevin
Hello,
I just wanted to add that there is one write-able item : aleos.mdm.reserve_ser0.
This item is for requesting to reserve access to the RS232 port for the EAF application.
This item is an integer, its value is 0 when ALEOS system holds the serial port and 1 when the EAF application holds it.
You can write it with 0/1 value to reserve/release the serial port for the EAF application.
(If you use that parameter and then use the serial port, please note that you need to reboot the device so that the serial reservation is updated in the system).
Laurent