A reproductible crashing bug on last git version (r1520.b170a8e, with ArchLinux):

• Launch tic80
• demo
• load bpp
• go to sprite editor
• activate advanced mode
• Set BPP 1 bit per pxiel
• activate BPP 1 bit per mode
• Click on Srpites [tab] (par opposition to tiles) => crash

Backtrace from gdb (not so much debug strings):

(gdb) bt
#0  0x00007ffff7a75ef5 in raise () from /usr/lib/libc.so.6
#1  0x00007ffff7a5f862 in abort () from /usr/lib/libc.so.6
#2  0x00007ffff7ab7f78 in __libc_message () from /usr/lib/libc.so.6
#3  0x00007ffff7b47a1a in __fortify_fail () from /usr/lib/libc.so.6
#4  0x00007ffff7b462b4 in __chk_fail () from /usr/lib/libc.so.6
#5  0x00007ffff7ab079d in _IO_str_chk_overflow () from /usr/lib/libc.so.6
#6  0x00007ffff7abc1e1 in _IO_default_xsputn () from /usr/lib/libc.so.6
#7  0x00007ffff7aa51b9 in __vfprintf_internal () from /usr/lib/libc.so.6
#8  0x00007ffff7ab0844 in __vsprintf_internal () from /usr/lib/libc.so.6
#9  0x00007ffff7b45d9f in __sprintf_chk () from /usr/lib/libc.so.6
#10 0x00005555555bb9cd in ?? ()
#11 0x00005555555a7b98 in ?? ()
#12 0x000055555559c974 in main ()