diff --git a/src/main/scala/li/cil/oc/common/component/TextBuffer.scala b/src/main/scala/li/cil/oc/common/component/TextBuffer.scala
index 755aa3563..5383ddf53 100644
--- a/src/main/scala/li/cil/oc/common/component/TextBuffer.scala
+++ b/src/main/scala/li/cil/oc/common/component/TextBuffer.scala
@@ -648,12 +648,12 @@ object TextBuffer {
 
     override def onBufferSet(col: Int, row: Int, s: String, vertical: Boolean) {
       super.onBufferSet(col, row, s, vertical)
-      dirty = true
+      markDirty()
     }
 
     override def onBufferBitBlt(col: Int, row: Int, w: Int, h: Int, id: Int, fromCol: Int, fromRow: Int): Unit = {
       super.onBufferBitBlt(col, row, w, h, id, fromCol, fromRow)
-      dirty = true
+      markDirty()
     }
 
     override def onBufferRamInit(id: Int, buffer: TextBufferProxy): Unit = {
diff --git a/src/main/scala/li/cil/oc/server/component/GraphicsCard.scala b/src/main/scala/li/cil/oc/server/component/GraphicsCard.scala
index 28f43e5bc..2b0909594 100644
--- a/src/main/scala/li/cil/oc/server/component/GraphicsCard.scala
+++ b/src/main/scala/li/cil/oc/server/component/GraphicsCard.scala
@@ -232,7 +232,7 @@ class GraphicsCard(val tier: Int) extends prefab.ManagedEnvironment with DeviceI
           if (dstIdx == srcIdx) {
             val tx = col - fromCol
             val ty = row - fromRow
-            dst.copy(col, row, w, h, tx, ty)
+            dst.copy(fromCol - 1, fromRow - 1, w, h, tx, ty)
             result(true)
           } else {
             // at least one of the two buffers is a gpu buffer
@@ -454,8 +454,6 @@ class GraphicsCard(val tier: Int) extends prefab.ManagedEnvironment with DeviceI
     val vertical = args.optBoolean(3, false)
 
     screen(s => {
-      val x2 = if (vertical) x else x + value.length - 1
-      val y2 = if (!vertical) y else y + value.length - 1
       if (consumeViewportPower(s, context, setCosts(tier), value.length, Settings.get.gpuSetCost)) {
         s.set(x, y, value, vertical)
         result(true)