What are the document requirements and process for extending a non-O visa in Thailand based on an embassy letter?

Report from Koh Samui:

Task: extension based on embassy letter, after non-o + a few covid extensions.

Passports: 1 Ukrainian, 1 russian.

Documents needed (TWO of each):

- TM7

- STM

- Acknolewdgement of overstay penalties

- copy of 1st passport page and all pages with current stamps/visas. Strictly horizontal on A4 (specifically states that).

- copy of TM6

- letter from embassy

- printout from Google Maps showing house location and coordinates (longtitude and latitude)

- TM30

- photo

For russian passport, have to bring original letter + 1 copy (since you get those letters in person). For Ukrainian passport, in addition to letter printout (letters are sent by email by consulate) they also asked for a printout of actual email text translated into English via Google Translate.

Process was super tiresome, probably 10x longer than covid extension - we came at 8:35 with all forms already filled in and all documents ready (except for those extra printouts), spent 2.5 hours.

Got under consideration stamp for 17 days (April 4th).