Some extensive background - some of it technical - follows. So bear with me, this is rather interesting story. I had merrily forgotten all about it, but it has already been 14 years since I last laid eyes on that particular code fragment...

Issue: Amiga and UNIX LhA archives are incompatible. That is you can have a old Amiga LhA archive that cannot be decompressed with UNIX LhA. Similarly, you can have a UNIX LhA archive that cannot be decompressed with Amiga LhA. The actual difference is regarding what values the algorithm can expect to find from the dictionary: ' ' (space) or 0 (zero). Amiga LhA uses zero, UNIX LhA uses space.

I believe the problem was solved at some point by making sure that Amiga LhA compressor creates archives that are compatible with the UNIX LhA in all situations. I believe this might actually result in slightly larger archives vs the older incompatible compressor. However, this cannot possibly fix the already existing incompatible archives.

Sometime around the same time a decision was made to modify the Amiga LhA decompressor to work similar to the UNIX LhA: That is, it would fail with those older archives.

Now, here comes the dilemma: The new LhA would create archives that are always ok, regardless of which LhA you used to decompress them. However: It would now itself fail to decompress the old incompatible Amiga LhA archives that had been created earlier! I didn't like that much, since for example it lead to the situation where many existing Amiga LhA archives would just fail to extract. So I made it so that MorphOS LhA worked with the Amiga LhA archives in this corner case, instead of the UNIX ones.

Now, this meant that occasionally you would run into UNIX LhA archives that MorphOS LhA command would fail to extract. And this is exactly what is happening here.

To remedy the situation I decided to create somewhat of a hack:
1. By default I now expect to get UNIX like archive at decompress.
2. If an CRC error occurs I will try to decompress it again with the old AMIGA LhA specific setup. If the checksum is correct now the extract succeeds.

This LhA version (2.7.14) will be available in the next MorphOS release.