diff --git a/README.md b/README.md
index dafb655..10514a8 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,8 @@ cd minimap2 && make
 # use presets (no test data)
 ./minimap2 -ax map-pb ref.fa pacbio.fq.gz > aln.sam       # PacBio CLR genomic reads
 ./minimap2 -ax map-ont ref.fa ont.fq.gz > aln.sam         # Oxford Nanopore genomic reads
-./minimap2 -ax map-hifi ref.fa pacbio-ccs.fq.gz > aln.sam # PacBio HiFi/CCS genomic reads
+./minimap2 -ax asm20 ref.fa pacbio-ccs.fq.gz > aln.sam    # PacBio HiFi/CCS genomic reads (v2.18)
+./minimap2 -ax map-hifi ref.fa pacbio-ccs.fq.gz > aln.sam # PacBio HiFi/CCS genomic reads (GitHub HEAD)
 ./minimap2 -ax sr ref.fa read1.fa read2.fa > aln.sam      # short genomic paired-end reads
 ./minimap2 -ax splice ref.fa rna-reads.fa > aln.sam       # spliced long reads (strand unknown)
 ./minimap2 -ax splice -uf -k14 ref.fa reads.fa > aln.sam  # noisy Nanopore Direct RNA-seq
@@ -253,7 +254,7 @@ To avoid this issue, you can add option `-L` at the minimap2 command line.
 This option moves a long CIGAR to the `CG` tag and leaves a fully clipped CIGAR
 at the SAM CIGAR column. Current tools that don't read CIGAR (e.g. merging and
 sorting) still work with such BAM records; tools that read CIGAR will
-effectively ignore these records. It has been decided that future tools will
+effectively ignore these records. It has been decided that future tools
 will seamlessly recognize long-cigar records generated by option `-L`.
 
 **TL;DR**: if you work with ultra-long reads and use tools that only process
@@ -274,7 +275,7 @@ CGATCGATAAATAGAGTAG---GAATAGCA
 CGATCG---AATAGAGTAGGTCGAATtGCA
 ```
 is represented as `:6-ata:10+gtc:4*at:3`, where `:[0-9]+` represents an
-identical block, `-ata` represents a deltion, `+gtc` an insertion and `*at`
+identical block, `-ata` represents a deletion, `+gtc` an insertion and `*at`
 indicates reference base `a` is substituted with a query base `t`. It is
 similar to the `MD` SAM tag but is standalone and easier to parse.
 
diff --git a/python/README.rst b/python/README.rst
index 3d0fae8..3082980 100644
--- a/python/README.rst
+++ b/python/README.rst
@@ -144,7 +144,7 @@ properties:
 * **mlen**: length of the matching bases in the alignment, excluding ambiguous
   base matches.
 
-* **NM**: number of mismatches, gaps and ambiguous poistions in the alignment
+* **NM**: number of mismatches, gaps and ambiguous positions in the alignment
 
 * **trans_strand**: transcript strand. +1 if on the forward strand; -1 if on the
   reverse strand; 0 if unknown