[Spade] Cleanly compiled firmware doesn't boot properly

**Describe the bug**
Flashing a freshly built Spade (firmware/spade) onto a Sprig hardware will cause the OS not to boot and show a screen with each pixel being random colors.

**To Reproduce**
Steps to reproduce the behavior:
1. Build Spade from source at [repo root]/firmware/spade with your desired method
2. Flash the firmware on a Sprig which has been just obtained, or flash a Pico nuke file to clear the Pico's memory, then flash your firmware next.
3. Observe how your Spade doesn't boot.

**Expected behavior**
Spade should show the main menu and ask for game upload.

**Actual behavior**
A screen with randomly-colored pixels is shown.

**Screenshots**

Start by building the firmware from [repo root]/firmware/spade, then reproduce the issue by flashing it onto a Sprig or a Pico cleared with a Pico nuke file. Compare the resulting random-pixel screen with the expected main menu and game-upload prompt; done means a freshly built Spade boots correctly.

Written by the indexing model from the issue text.