Re: Stretching
I think you're conflating two different things.
The plaintiff (don't know what it's called in what'd be a US equivalent German civil courts) was missing required components so that they could update that LGPL-covered code to do what they wanted with that component's logging. Whether those changes were persistent across reboots or entered in manually via CLI after reboot doesn't have any bearing here.
The concern here was that uclibc's license requires where it is statically linked to an application, that that application be provided at a minimum as an object, so that, in the author's own words, "[t]his will (in theory) allow your customers to apply uClibc bug fixes to your application." [0]
Also, I am presuming that AVM statically linked the library in their application, since uclibc's license states, "[y]ou can distribute a closed source application which is linked with an unmodified uClibc shared library. In this case, you do not need to give away any source code for your application." [0]
As I stated previously - it was the prior decisions made by AVM here that forced their own hands before the Court, not the plaintiff.
[0] - https://uclibc.org/FAQ.html#licensing