diff --git a/_fixtures/fncall.go b/_fixtures/fncall.go
index 6967e102..326ebade 100644
--- a/_fixtures/fncall.go
+++ b/_fixtures/fncall.go
@@ -176,6 +176,17 @@ func regabistacktest2(n1, n2, n3, n4, n5, n6, n7, n8, n9, n10 int) (int, int, in
 	return n1 + n2, n2 + n3, n3 + n4, n4 + n5, n5 + n6, n6 + n7, n7 + n8, n8 + n9, n9 + n10, n10 + n1
 }
 
+type Issue2698 struct {
+	a uint32
+	b uint8
+	c uint8
+	d uintptr
+}
+
+func (i Issue2698) String() string {
+	return fmt.Sprintf("%d %d %d %d", i.a, i.b, i.c, i.d)
+}
+
 func main() {
 	one, two := 1, 2
 	intslice := []int{1, 2, 3}
@@ -192,6 +203,12 @@ func main() {
 	var pable_pa PRcvrable = pa
 	var x X = 2
 	var x2 X2 = 2
+	issue2698 := Issue2698{
+		a: 1,
+		b: 2,
+		c: 3,
+		d: 4,
+	}
 
 	fn2clos := makeclos(pa)
 	fn2glob := call1
@@ -208,5 +225,5 @@ func main() {
 	d.Method()
 	d.Base.Method()
 	x.CallMe()
-	fmt.Println(one, two, zero, call, call0, call2, callexit, callpanic, callbreak, callstacktrace, stringsJoin, intslice, stringslice, comma, a.VRcvr, a.PRcvr, pa, vable_a, vable_pa, pable_pa, fn2clos, fn2glob, fn2valmeth, fn2ptrmeth, fn2nil, ga, escapeArg, a2, square, intcallpanic, onetwothree, curriedAdd, getAStruct, getAStructPtr, getVRcvrableFromAStruct, getPRcvrableFromAStructPtr, getVRcvrableFromAStructPtr, pa2, noreturncall, str, d, x, x2.CallMe(5), longstrs, regabistacktest, regabistacktest2)
+	fmt.Println(one, two, zero, call, call0, call2, callexit, callpanic, callbreak, callstacktrace, stringsJoin, intslice, stringslice, comma, a.VRcvr, a.PRcvr, pa, vable_a, vable_pa, pable_pa, fn2clos, fn2glob, fn2valmeth, fn2ptrmeth, fn2nil, ga, escapeArg, a2, square, intcallpanic, onetwothree, curriedAdd, getAStruct, getAStructPtr, getVRcvrableFromAStruct, getPRcvrableFromAStructPtr, getVRcvrableFromAStructPtr, pa2, noreturncall, str, d, x, x2.CallMe(5), longstrs, regabistacktest, regabistacktest2, issue2698.String())
 }
diff --git a/pkg/dwarf/op/regs.go b/pkg/dwarf/op/regs.go
index 88dcf23f..7696b928 100644
--- a/pkg/dwarf/op/regs.go
+++ b/pkg/dwarf/op/regs.go
@@ -164,3 +164,20 @@ func (reg *DwarfRegister) FillBytes() {
 	reg.Bytes = make([]byte, 8)
 	binary.LittleEndian.PutUint64(reg.Bytes, reg.Uint64Val)
 }
+
+// Overwrite takes the contents of reg1 and overwrites them with the contents
+// of reg2 in little-endian order, returning a new register. The new register
+// will always contain the complete contents of both registers, so if reg2 is
+// larger than reg1, the final register will be reg2's size.
+func (reg1 *DwarfRegister) Overwrite(reg2 *DwarfRegister) *DwarfRegister {
+	reg1.FillBytes()
+	reg2.FillBytes()
+	width := len(reg1.Bytes)
+	if len(reg2.Bytes) > len(reg1.Bytes) {
+		width = len(reg2.Bytes)
+	}
+	b := make([]byte, width)
+	copy(b, reg1.Bytes)
+	copy(b, reg2.Bytes)
+	return DwarfRegisterFromBytes(b)
+}
diff --git a/pkg/proc/dwarf_expr_test.go b/pkg/proc/dwarf_expr_test.go
index 51860728..439bb578 100644
--- a/pkg/proc/dwarf_expr_test.go
+++ b/pkg/proc/dwarf_expr_test.go
@@ -245,7 +245,7 @@ func TestDwarfExprComposite(t *testing.T) {
 	if changeCalls[0] != "3 - 2f00000000000000" {
 		t.Errorf("wrong call to SetReg (Rbx)")
 	}
-	if changeCalls[1] != "2 - 0c00" {
+	if changeCalls[1] != "2 - 0c00000000000000" {
 		t.Errorf("wrong call to SetReg (Rcx)")
 	}
 	if mem.data[0x10] != 13 || mem.data[0x11] != 0x00 {
diff --git a/pkg/proc/mem.go b/pkg/proc/mem.go
index 281a0158..cb2a35f6 100644
--- a/pkg/proc/mem.go
+++ b/pkg/proc/mem.go
@@ -179,7 +179,9 @@ func (mem *compositeMemory) WriteMemory(addr uint64, data []byte) (int, error) {
 
 			switch piece.Kind {
 			case op.RegPiece:
-				err := mem.regs.ChangeFunc(piece.Val, op.DwarfRegisterFromBytes(pieceMem))
+				oldReg := mem.regs.Reg(piece.Val)
+				newReg := op.DwarfRegisterFromBytes(pieceMem)
+				err := mem.regs.ChangeFunc(piece.Val, oldReg.Overwrite(newReg))
 				if err != nil {
 					return donesz, err
 				}
diff --git a/service/test/variables_test.go b/service/test/variables_test.go
index 95a2c8e1..44474084 100644
--- a/service/test/variables_test.go
+++ b/service/test/variables_test.go
@@ -1286,6 +1286,7 @@ func TestCallFunction(t *testing.T) {
 	var testcases117 = []testCaseCallFunction{
 		{`regabistacktest("one", "two", "three", "four", "five", 4)`, []string{`:string:"onetwo"`, `:string:"twothree"`, `:string:"threefour"`, `:string:"fourfive"`, `:string:"fiveone"`, ":uint8:8"}, nil},
 		{`regabistacktest2(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)`, []string{":int:3", ":int:5", ":int:7", ":int:9", ":int:11", ":int:13", ":int:15", ":int:17", ":int:19", ":int:11"}, nil},
+		{`issue2698.String()`, []string{`:string:"1 2 3 4"`}, nil},
 	}
 
 	withTestProcessArgs("fncall", t, ".", nil, protest.AllNonOptimized, func(p *proc.Target, fixture protest.Fixture) {