diff --git a/src/cmd/ksh93/bltins/typeset.c b/src/cmd/ksh93/bltins/typeset.c
index 80761dd47..fe7d036c4 100644
--- a/src/cmd/ksh93/bltins/typeset.c
+++ b/src/cmd/ksh93/bltins/typeset.c
@@ -732,7 +732,8 @@ static int     setall(char **argv,register int flag,Dt_t *troot,struct tdata *tp
 			np = nv_open(name,troot,nvflags|((nvflags&NV_ASSIGN)?0:NV_ARRAY)|((iarray|(nvflags&(NV_REF|NV_NOADD)==NV_REF))?NV_FARRAY:0));
 			if(!np)
 				continue;
-			if(np->nvflag&NV_RDONLY && !tp->pflag && (flag & ~NV_NOFREE) != NV_RDONLY)
+			if(np->nvflag&NV_RDONLY && !tp->pflag
+			&& (flag & ~(NV_ASSIGN|NV_RDONLY|NV_EXPORT)))	/* allow readonly/export on readonly vars */
 			{
 				errormsg(SH_DICT,ERROR_exit(1),e_readonly,nv_name(np));
 				UNREACHABLE();
diff --git a/src/cmd/ksh93/tests/readonly.sh b/src/cmd/ksh93/tests/readonly.sh
old mode 100644
new mode 100755
index cb8c29b11..778c54090
--- a/src/cmd/ksh93/tests/readonly.sh
+++ b/src/cmd/ksh93/tests/readonly.sh
@@ -331,5 +331,14 @@ do
 done
 unset i n got rtests
 
+# ======
+# readonly variables should still accept setting the readonly or export attributes
+# https://github.com/ksh93/ksh/issues/258
+(readonly v=1; readonly v) 2>/dev/null || err_exit "readonly variable cannot be set readonly (1)"
+(readonly v=1; typeset -r v) 2>/dev/null || err_exit "readonly variable cannot be set readonly (2)"
+(readonly v=1; export v) 2>/dev/null || err_exit "readonly variable cannot be exported (1)"
+(readonly v=1; typeset -x v) 2>/dev/null || err_exit "readonly variable cannot be exported (2)"
+(readonly v=1; typeset -rx v) 2>/dev/null || err_exit "readonly variable cannot be set readonly and exported"
+
 # ======
 exit $((Errors<125?Errors:125))