One more thing, trying to print the
rocket 🚀 at U+1F680 (UTF-8 Surrogate pair U+D83D U+DE80) defies the parser

...more Unicode fun.
Code:
[root@kindle us]# fbink -t regular=/mnt/us/linkfonts/fonts/unscii-8.otf,size=86 -o -M -m -c < u1F680
[FBInk] Enabled Legacy einkfb Kindle quirks
[FBInk] Clock tick frequency appears to be 100 Hz
[FBInk] Screen density set to 167 dpi
[FBInk] Variable fb info: 600x800, 4bpp @ rotation: 0 (Upright, 0°)
[FBInk] Fontsize set to 16x16 (IBM base glyph size: 8x8)
[FBInk] Line length: 37 cols, Page size: 50 rows
[FBInk] Fixed fb info: ID is "eink_fb", length of fb mem: 483328 bytes & line length: 300 bytes
[FBInk] Pen colors set to #000000 -> #FFFFFF for the foreground and #FFFFFF -> #000000 for the background
[FBInk] Codepoint U+D83D is not covered by this font!
[FBInk] Codepoint U+DE80 is not covered by this font!
[root@kindle us]#