--html presenter hangs (maybe squashfs unpack related)

I'm trying to compare two small files and get the HTML output. Sadly the --html presenter hangs forever, other presenters work just fine.

aparcar@mass:~/openwrt-rebuilder$ diffoscope rebuild/bin/targets/ath79/generic/openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin --html test.html --progress --max-report-size 10 --debug
2020-11-06 21:40:33 D: diffoscope.main: Starting diffoscope 161
2020-11-06 21:40:33 D: diffoscope.main: Free space in temporary directory: 167.84 GiB
2020-11-06 21:40:33 D: diffoscope.presenters.formats: Will generate the following presenter formats: html
2020-11-06 21:40:33 W: diffoscope.config: max_report_size (10) < default value of max_page_size (41943040), setting latter to 10
2020-11-06 21:40:33 D: diffoscope.environ: Normalising locale, timezone, etc. Inheriting PATH of /home/aparcar/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
2020-11-06 20:40:33 D: diffoscope.main: Starting comparison
2020-11-06 20:40:33 D: diffoscope.comparators.decompile: radare2 not found, disabling decompiler
2020-11-06 20:40:33 D: diffoscope.comparators: Loaded 78 comparator classes
2020-11-06 20:40:33 D: diffoscope.comparators.utils.specialize: rebuild/bin/targets/ath79/generic/openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin not identified by any comparator. Magic says: u-boot legacy uImage, MIPS OpenWrt Linux-5.4.74, Linux/MIPS, OS Kernel Image (lzma), 2138842 bytes, Thu Nov  5 19:29:48 2020, Load Address: 0x80060000, Entry Point: 0x80060000, Header CRC: 0x79B33A37, Data CRC: 0x1C498561
2020-11-06 20:40:33 D: diffoscope.comparators.utils.specialize: openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin not identified by any comparator. Magic says: u-boot legacy uImage, MIPS OpenWrt Linux-5.4.74, Linux/MIPS, OS Kernel Image (lzma), 2138833 bytes, Thu Nov  5 19:29:48 2020, Load Address: 0x80060000, Entry Point: 0x80060000, Header CRC: 0xD3EA706D, Data CRC: 0x5FC1AE14
2020-11-06 20:40:33 D: diffoscope.comparators.utils.compare: Comparing rebuild/bin/targets/ath79/generic/openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin (FilesystemFile) and openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin (FilesystemFile)
2020-11-06 20:40:33 D: diffoscope.comparators.utils.specialize: rebuild/bin/targets/ath79/generic/openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin not identified by any comparator. Magic says: u-boot legacy uImage, MIPS OpenWrt Linux-5.4.74, Linux/MIPS, OS Kernel Image (lzma), 2138842 bytes, Thu Nov  5 19:29:48 2020, Load Address: 0x80060000, Entry Point: 0x80060000, Header CRC: 0x79B33A37, Data CRC: 0x1C498561
2020-11-06 20:40:33 D: diffoscope.comparators.utils.specialize: openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin not identified by any comparator. Magic says: u-boot legacy uImage, MIPS OpenWrt Linux-5.4.74, Linux/MIPS, OS Kernel Image (lzma), 2138833 bytes, Thu Nov  5 19:29:48 2020, Load Address: 0x80060000, Entry Point: 0x80060000, Header CRC: 0xD3EA706D, Data CRC: 0x5FC1AE14
2020-11-06 20:40:33 D: diffoscope.comparators.utils.file: has_same_content(rebuild/bin/targets/ath79/generic/openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin, openwrt-ath79-generic-tplink_archer-c7-v5-squashfs-sysupgrade.bin)
2020-11-06 20:40:33 D: diffoscope.comparators.utils.command: Executing xxd {}
2020-11-06 20:40:34 D: diffoscope.comparators.utils.command: Executing xxd {}
2020-11-06 20:40:34 D: diffoscope.tempfiles: Created top-level temporary directory: /tmp/diffoscope_11aty5xl
2020-11-06 20:40:34 D: diffoscope.diff: Running diff -aU7 /tmp/diffoscope_11aty5xl/tmpnht6no76/fifo1 /tmp/diffoscope_11aty5xl/tmpnht6no76/fifo2
2020-11-06 20:40:36 D: diffoscope.diff: diff -aU7 /tmp/diffoscope_11aty5xl/tmpnht6no76/fifo1 /tmp/diffoscope_11aty5xl/tmpnht6no76/fifo2: returncode 1, parsed True
2020-11-06 20:40:36 D: diffoscope.presenters.formats: Generating 'html' output at 'test.html'