SUMI Converter

Global Settings

Split landscape spreads Auto-detect chapters Optimize images for e-ink

EPUB Optimization

Strip all CSS (plain text look) Clean CSS (remove colors, backgrounds, web fonts) Fix malformed XHTML tags Fix encoding issues (smart quotes, accents) Strip junk files (.DS_Store, __MACOSX)

Smart Detection

📖 Book — text PDFs (with inline images preserved), DOCX, TXT, MD, HTML, FB2, RTF → EPUB
📰 Comic — CBZ or image-heavy PDFs → EPUB
🔄 Manga — CBZ with RTL metadata or naming → EPUB (RTL)
📜 Manhwa — CBZ with tall strip images → EPUB (segments)
📋 Document — scanned PDFs → EPUB (images)
🖼 Image — JPG, PNG, SVG, etc. → BMP (sleep/viewer)
🎴 Flashcard — CSV, TSV, JSON → flashcard file
✅ EPUB — full optimization: resize images to 480×800, grayscale, strip fonts/JS, clean CSS, fix encoding

SD Card Output

/books/ — book EPUBs
/comics/ — comic & manga EPUBs
/images/ — converted BMPs
/sleep/ — sleep screen BMPs
/flashcards/ — card decks
Just extract the ZIP — each folder maps to a SUMI category.

📲 Wireless Transfer

Send files directly to SUMI via Bluetooth — no SD card removal needed.
Requires Chrome/Edge. ~15-30KB/s transfer speed.

⌨️ Using a BLE page turner?

Page-turning while a Bluetooth remote is paired needs the book to be pre-rendered first. Without it, NimBLE's ~48 KB resident memory plus the EPUB parser's allocations on a long chapter can run the device out of heap mid-turn.

After converting here, drop the EPUB into /process/ to produce an XTC bundle — the reader skips the parser entirely for XTC, so BLE page turns stay stable across any chapter length. Tap-the-button reading on the device itself works fine on a plain EPUB; this prerequisite only matters once you pair a turner.

Recent firmware (SUMI 0.6.2 and up, Folio 0.1.1 and up) removed the on-device "Index for faster reading" option, so pre-rendering on the desktop is the only path to a parser-free reading session.