I have the same issue with my One SL. I've tried with wireless and a patch cable connected to my router, the end result is the same. I set up another SL three weeks ago without any issues.

Is it possible to download a low-level log file from the system for diagnostics? 

I have the same issue with a Play:1 that I bought recently refurbished from Sonos. The first setup seemed to be working (VERY slowly) but eventually froze with the speaker flashing red. I tried to start again and now the app barely thinks about updating before throwing up the error (1002/36), despite over 10 factory resets, connecting to ethernet (and leaving like that overnight) and anything else I could think of. The speaker just sits there flashing green and is detected in the app but refuses to update. Any help appreciated as the contact centre is clearly swamped given the recent app failures.

So I just encountered this problem with a refurb beam sl purchased from Sonos. Multiple factory resets, app reinstalls, etc. I tried from 4 different Android devices, as well as an update from the windows app. Same error every time.

On 2 occasions I got the prompt to connect to the beam's private network to update, and then the Sonos app would crash. Tried on another phone but that update never finished. I left one going overnight. 

Most of these attempts with the beam hard wired into the network. 

This morning I made sure my phone was on the 2.4 Ghz wireless network, and disconnected the beam from wired Ethernet. Started the update process again, and it prompted to connect to beam's private network and this time the beam started flashing orange and white. Finally had success... So I have no idea what the actual issue was

Any luck yet ?

I have same issue on one of my speakers. Triede patch cabel and 400 resets of both speaker and router.

I solved this with Sonos support by performing the update using their Windows program instead of the Android app. 

Same Issue. Solved it by downloading S1 app and adding it to S1. It updated no problem. Then did factory reset and added it to S2. Problem solved.