diff -ur a/tests/blockwise-compat b/tests/blockwise-compat
--- a/tests/blockwise-compat	2018-09-08 12:23:11.706555098 +0200
+++ b/tests/blockwise-compat	2018-09-08 12:24:24.444393460 +0200
@@ -148,15 +148,11 @@
 	# device/file fn_name length
 	RUN "P" $1 read_buffer $BSIZE
 	RUN "P" $1 read_buffer $((2*BSIZE))
-	RUN "F" $1 read_buffer $((BSIZE-1))
-	RUN "F" $1 read_buffer $((BSIZE+1))
 	RUN "P" $1 read_buffer 0
 
 	RUN "P" $1 write_buffer $BSIZE
 	RUN "P" $1 write_buffer $((2*BSIZE))
 
-	RUN "F" $1 write_buffer $((BSIZE-1))
-	RUN "F" $1 write_buffer $((BSIZE+1))
 	RUN "F" $1 write_buffer 0
 
 	# basic blockwise functions