diff --git a/.github/dev.yml b/.github/dev.yml
index 924fdae..eb3a62f 100644
--- a/.github/dev.yml
+++ b/.github/dev.yml
@@ -1,7 +1,7 @@
 pr: none
 trigger: [ master ]
 
-name: 3.6.5-dev.$(Rev:r)
+name: 3.6.6-dev.$(Rev:r)
 
 pool:
   vmImage: ubuntu-latest
diff --git a/FAQ.md b/FAQ.md
index 2a56bdd..84d0df4 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -235,7 +235,7 @@ In particular, it will detect and handle automatically and properly the various
 * 2FA password required (your Config needs to provide "password")
 * Email registration procedure required (your Config needs to provide "email", "email_verification_code")
 * Account registration/sign-up required (your Config needs to provide "first_name", "last_name")
-* Request to resend the verification code through alternate ways like SMS (if your Config answer an empty "verification_code" initially)
+* Request to resend the verification code through alternate ways (if your Config answer an empty "verification_code" initially)
 * Transient failures, slowness to respond, wrong code/password, checks for encryption key safety, etc..
 
 Contrary to TLSharp, WTelegramClient supports MTProto v2.0 (more secured), transport obfuscation, protocol security checks, MTProto [Proxy](EXAMPLES.md#proxy), real-time updates, multiple DC connections, API documentation in Intellisense...
diff --git a/src/Client.Helpers.cs b/src/Client.Helpers.cs
index 4bed1ae..c0ac2f1 100644
--- a/src/Client.Helpers.cs
+++ b/src/Client.Helpers.cs
@@ -317,7 +317,7 @@ namespace WTelegram
 			var client = dc_id == 0 ? this : await GetClientForDC(dc_id, true);
 			using var writeSem = new SemaphoreSlim(1);
 			bool canSeek = outputStream.CanSeek;
-			long streamStartPos = outputStream.Position;
+			long streamStartPos = canSeek ? outputStream.Position : 0;
 			long fileOffset = 0, maxOffsetSeen = 0;
 			long transmitted = 0;
 			var tasks = new Dictionary<long, Task>();
@@ -373,7 +373,7 @@ namespace WTelegram
 						await writeSem.WaitAsync();
 						try
 						{
-							if (streamStartPos + offset != outputStream.Position) // if we're about to write out of order
+							if (canSeek && streamStartPos + offset != outputStream.Position) // if we're about to write out of order
 							{
 								await outputStream.FlushAsync(); // async flush, otherwise Seek would do a sync flush
 								outputStream.Seek(streamStartPos + offset, SeekOrigin.Begin);