The GXV3000 is an old phone from Grandstream, not anymore in production and supported, but still available on Ebay at a decent price.
It is possible to even find in Ebay "new" GXV3000, i.e. never used before, like one I bought recently as a replacement for a broken one.
So I had to go back on memory lane in order to update the firmware in it to the last available one (high recommended in order to fix the SPIT problem)
Here what is needed to do the job.
