Request

Add the Bitcoin sign character (₿, U+20BF) to the built-in Montserrat fonts so apps can display it natively.

Background

The current Montserrat-Medium.ttf (v7.200) does not include U+20BF. The Lightning Piggy app comments this out:

#balance_text = "₿ " + str(balance) # font doesnt support it

The latest Montserrat (v9.000) from Google Fonts includes ₿ along with other currency symbols.

Changes Required

1. Update the font source

Replace lvgl_micropython/lib/lvgl/scripts/built_in_font/Montserrat-Medium.ttf with the latest version from:

https://github.com/JulietaUla/Montserrat/raw/master/fonts/ttf/Montserrat-Medium.ttf

2. Add U+20BF to the glyph range

In lvgl_micropython/lib/lvgl/scripts/built_in_font/built_in_font_gen.py, line 23:

# Before:
default=['0x20-0x7F,0xB0,0x2022'],
# After:
default=['0x20-0x7F,0xB0,0x2022,0x20BF'],

3. Regenerate all font .c files

cd lvgl_micropython/lib/lvgl/scripts/built_in_font
# For each size (8, 10, 12, ... 48):
npx lv_font_conv --no-compress --no-prefilter --bpp 4 --size SIZE \
  --font Montserrat-Medium.ttf -r 0x20-0x7F,0xB0,0x2022,0x20BF \
  --font FontAwesome5-Solid+Brands+Regular.woff -r FONTAWESOME_SYMBOLS \
  --format lvgl -o ../../src/font/lv_font_montserrat_SIZE.c --force-fast-kern-format

# Fix includes:
sed -i 's|#include "lvgl.h"|#include "../../lvgl.h"|' ../../src/font/lv_font_montserrat_*.c

Or use the existing generate_all.py script after applying step 2.

4. Rebuild firmware

Size impact

Minimal — one additional glyph per font size (a few bytes each).

Usage

After this change, apps can use the Bitcoin symbol directly:

balance_label.set_text("₿ " + str(balance))
# or with \u20bf
balance_label.set_text("\u20bf " + str(balance))

🤖 Generated with Claude Code