The law is rather clear on this issue. The litmus test for determining
breach of warranty is a balance between the
warranty literature for the product and
intended use of the product. In this instance, the
intended use of the product is determined by the product manual, marketing material, advertisements, other collateral material, and the
industry standard use for similar consumer grade products.
If, for example, D-Link included functionality in a product specifically intended to install third-party applications/add-ons with no counter language or clause explicitly or implicitly dissuading the use of non-D-Link software, then one could strongly argue that installing a third-party software product would not constitute a breach of warranty.
I should also put out there that
"system modification" is a highly ambiguous term at best. If a product is used for its
intended purpose, then one could argue that the system is not modified, since a
system modification would require a non-sanctioned use resulting in a deviation from the product's
intended purpose. This is a rather liberal interpretation of
system modification. You will have to look at D-Link's definition of
system modification or the industry standard definition if no D-Link definition exists. This argument (under U.S. law) falls under the legal doctrine of an
implied warranty of fitness for a particular purpose.Since I have not read the DNS-320 warranty language, nor have I examined all of the DNS-320 literature pertaining to third-party add-ons in sufficient detail, I'm not in a position to pass judgement one way or the other. I'll leave that for you to decide.
My arguments presented in this thread are intended for discussion purposes only and are not intended to be relied upon for rendering legal decisions for determining in-warranty versus out-of-warranty use of the DNS-320