diff --git a/lib/pure/os.nim b/lib/pure/os.nim
index 1fd08e7636..3e24ce57b5 100644
--- a/lib/pure/os.nim
+++ b/lib/pure/os.nim
@@ -539,11 +539,11 @@ when not weirdTarget and (defined(freebsd) or defined(dragonfly) or defined(netb
 
 when not weirdTarget and (defined(linux) or defined(solaris) or defined(bsd) or defined(aix)):
   proc getApplAux(procPath: string): string =
-    result = newString(maxSymlinkLen)
-    var len = readlink(procPath, result.cstring, maxSymlinkLen)
+    result = newString(maxSymlinkLen+1) # TODO: fixme how to ?
+    var len = readlink(procPath, cast[cstring](addr result[0]), maxSymlinkLen)
     if len > maxSymlinkLen:
       result = newString(len+1)
-      len = readlink(procPath, result.cstring, len)
+      len = readlink(procPath, cast[cstring](addr result[0]), len)
     setLen(result, len)
 
 when not weirdTarget and defined(openbsd):
diff --git a/lib/pure/streams.nim b/lib/pure/streams.nim
index 8ae7fb3c1d..7691b2d16c 100644
--- a/lib/pure/streams.nim
+++ b/lib/pure/streams.nim
@@ -378,7 +378,7 @@ proc write*(s: Stream, x: string) =
         var x = x
         writeData(s, addr(x), x.len)
       else:
-        writeData(s, cstring(x), x.len)
+        writeData(s, addr x[0], x.len)
 
 proc write*(s: Stream, args: varargs[string, `$`]) =
   ## Writes one or more strings to the the stream. No length fields or
@@ -937,11 +937,12 @@ proc peekFloat64*(s: Stream): float64 =
   peek(s, result)
 
 proc readStrPrivate(s: Stream, length: int, str: var string) =
+  if length == 0: return
   if length > len(str): setLen(str, length)
   when defined(js):
     let L = readData(s, addr(str), length)
   else:
-    let L = readData(s, cstring(str), length)
+    let L = readData(s, addr(str[0]), length)
   if L != len(str): setLen(str, L)
 
 proc readStr*(s: Stream, length: int, str: var string) {.since: (1, 3).} =
@@ -963,11 +964,13 @@ proc readStr*(s: Stream, length: int): string =
   readStrPrivate(s, length, result)
 
 proc peekStrPrivate(s: Stream, length: int, str: var string) =
+  # TODO: fixme breaking changes: cannot modify strings by cstring
+  if length == 0: return
   if length > len(str): setLen(str, length)
   when defined(js):
     let L = peekData(s, addr(str), length)
   else:
-    let L = peekData(s, cstring(str), length)
+    let L = peekData(s, addr str[0], length)
   if L != len(str): setLen(str, L)
 
 proc peekStr*(s: Stream, length: int, str: var string) {.since: (1, 3).} =
diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim
index d1ffc4acbd..87a111f4a9 100644
--- a/lib/pure/strutils.nim
+++ b/lib/pure/strutils.nim
@@ -1981,7 +1981,7 @@ func find*(s: string, sub: char, start: Natural = 0, last = -1): int {.rtl,
       if length > 0:
         let found = c_memchr(s[start].unsafeAddr, sub, cast[csize_t](length))
         if not found.isNil:
-          return cast[int](found) -% cast[int](s.cstring)
+          return cast[int](found) -% cast[int](s[0].addr)
     else:
       findImpl()
 
diff --git a/lib/system/strs_v3.nim b/lib/system/strs_v3.nim
index 527e6c96a7..222729539a 100644
--- a/lib/system/strs_v3.nim
+++ b/lib/system/strs_v3.nim
@@ -144,7 +144,7 @@ proc nimToCStringConv(s: NimStringV3): cstring {.compilerproc, nonReloadable, in
   else:
     ## TODO: fixme: inject conversions somewhere else and be cleaned up
     ## but let it leak for now
-    let len = s.nimStrLenV3+1
+    let len = s.nimStrLenV3
     result = cast[cstring](allocShared0(len+1))
     copyMem(result, unsafeAddr s.p[0], len)