Trick to solve svk "Base checksum mismatch" error

Today my colleague found the read only svn mirror in our office LAN is out of sync, after I login to the machine and do svk sync manually, an error appears:

Retrieving log information from 198017 to 198224
A checksum mismatch occurred: Checksum mismatch for resulting fulltext
(/features/somefile.txt):
expected checksum: af8df88f2dcb0cdf37b0ae834f226f43
actual checksum: d1bb97b4f2a6559d4a8e1eda7aaba497

I guess it's because the host machine just crashed, but I can't find a way to recover the inconsistency.

Finally I found it can be fixed it by the following command:

svk sync -s 198015 -t 198016 //features

Then my sync script worked well again.