Fenix 8 Developer Mode

4503605 said:

When I read up on how to side load my prg file to the watch, this process involves setting the watch in developer mode. I can however not find this setting on my watch.

That's because "developer mode" doesn't exist on Garmin watches, regardless of what google ai, chatgpt, or any other llm may have told you.

4503605 said:

I should perhaps also add that my computer is a MacBook (M2) and connecting the watch does not "mount" it in such a way that I can transfer files to it.

Modern Garmin watches (and some of the newest Edge devices) use MTP for file transfer, as opposed to USB Mass Storage (as in very old Garmin watches and slightly old Edges).

Windows supports MTP natively, but macOS does not.

To transfer files to your Garmin device using macOS, you need 3rd party software such as https://openmtp.ganeshrvel.com/. Note that Garmin Express should be completely closed before using openmtp (including closing the Garmin icon in the menu bar). If you use openmtp often, you may wish to disable the option in Express which keeps Express open in the background.

It's too bad there's no official Garmin developer documentation which mentions this (afaik), despite the fact that MTP has been in use starting with the earliest Garmin watches which support music (released in 2018). Only conclusion I can draw is Garmin (as an org) doesn't care.

That's what the forums are for, right? For the "community" to provide free support where Garmin won't.

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MTP tech notes and background:

Advantages of MTP: operations are atomic (no need to eject device), no direct access to underlying filesystem (so it can't be corrupted, and it makes it easier for Garmin to prevent users from accessing sensitive data of arbitrary size, like Spotify music, without having to reserve a fixed amount of space for said data)

Disadvantages of MTP: slow, no direct access to files (e.g. to edit a file, you typically have to copy it from the device and back)

I'm fairly sure Garmin switched to MTP because they added support for on-board music / Spotify. Before that, they still had certain data which was inaccessible to the user (presumably on a different partition than the user-accessible partition via USB Mass Storage), but I think that approach would have required reserving a certain amount of space for a 2nd partition, which wouldn't be suitable for user data of fairly large and arbitrary size like music.

With MTP, both visible and "hidden" data can be on the same partition (in different folders), but Garmin can completely prevent access to the "hidden" data simply by not exposing it via MTP.