diff --git a/packages/firestore/src/index/ordered_code_writer.ts b/packages/firestore/src/index/ordered_code_writer.ts
index f94056df9d8..68b29c598ef 100644
--- a/packages/firestore/src/index/ordered_code_writer.ts
+++ b/packages/firestore/src/index/ordered_code_writer.ts
@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 import { debugAssert } from '../util/assert';
+import { ByteString } from '../util/byte_string';
 
 /** These constants are taken from the backend. */
 const MIN_SURROGATE = '\uD800';
@@ -25,6 +26,7 @@ const NULL_BYTE = 0xff; // Combined with ESCAPE1
 const SEPARATOR = 0x01; // Combined with ESCAPE1
 
 const ESCAPE2 = 0xff;
+const INFINITY = 0xff; // Combined with ESCAPE2
 const FF_BYTE = 0x00; // Combined with ESCAPE2
 
 const LONG_SIZE = 64;
@@ -110,6 +112,26 @@ export class OrderedCodeWriter {
   buffer = new Uint8Array(DEFAULT_BUFFER_SIZE);
   position = 0;
 
+  writeBytesAscending(value: ByteString): void {
+    const it = value[Symbol.iterator]();
+    let byte = it.next();
+    while (!byte.done) {
+      this.writeByteAscending(byte.value);
+      byte = it.next();
+    }
+    this.writeSeparatorAscending();
+  }
+
+  writeBytesDescending(value: ByteString): void {
+    const it = value[Symbol.iterator]();
+    let byte = it.next();
+    while (!byte.done) {
+      this.writeByteDescending(byte.value);
+      byte = it.next();
+    }
+    this.writeSeparatorDescending();
+  }
+
   /** Writes utf8 bytes into this byte sequence, ascending. */
   writeUtf8Ascending(sequence: string): void {
     for (const c of sequence) {
@@ -182,6 +204,24 @@ export class OrderedCodeWriter {
     }
   }
 
+  /**
+   * Writes the "infinity" byte sequence that sorts after all other byte
+   * sequences written in ascending order.
+   */
+  writeInfinityAscending(): void {
+    this.writeEscapedByteAscending(ESCAPE2);
+    this.writeEscapedByteAscending(INFINITY);
+  }
+
+  /**
+   * Writes the "infinity" byte sequence that sorts before all other byte
+   * sequences written in descending order.
+   */
+  writeInfinityDescending(): void {
+    this.writeEscapedByteDescending(ESCAPE2);
+    this.writeEscapedByteDescending(INFINITY);
+  }
+
   /**
    * Encodes `val` into an encoding so that the order matches the IEEE 754
    * floating-point comparison results with the following exceptions:
@@ -277,4 +317,10 @@ export class OrderedCodeWriter {
     newBuffer.set(this.buffer); // copy old data
     this.buffer = newBuffer;
   }
+
+  seed(encodedBytes: Uint8Array): void {
+    this.ensureAvailable(encodedBytes.length);
+    this.buffer.set(encodedBytes, this.position);
+    this.position += encodedBytes.length;
+  }
 }
diff --git a/packages/firestore/src/util/byte_string.ts b/packages/firestore/src/util/byte_string.ts
index f34efb44927..73b5cd1fa1a 100644
--- a/packages/firestore/src/util/byte_string.ts
+++ b/packages/firestore/src/util/byte_string.ts
@@ -43,6 +43,19 @@ export class ByteString {
     return new ByteString(binaryString);
   }
 
+  [Symbol.iterator](): Iterator<number> {
+    let i = 0;
+    return {
+      next: () => {
+        if (i < this.binaryString.length) {
+          return { value: this.binaryString.charCodeAt(i++), done: false };
+        } else {
+          return { value: undefined, done: true };
+        }
+      }
+    };
+  }
+
   toBase64(): string {
     return encodeBase64(this.binaryString);
   }
diff --git a/packages/firestore/test/unit/index/ordered_code_writer.test.ts b/packages/firestore/test/unit/index/ordered_code_writer.test.ts
index 5da6b78d0c7..823173ead14 100644
--- a/packages/firestore/test/unit/index/ordered_code_writer.test.ts
+++ b/packages/firestore/test/unit/index/ordered_code_writer.test.ts
@@ -20,6 +20,7 @@ import {
   numberOfLeadingZerosInByte,
   OrderedCodeWriter
 } from '../../../src/index/ordered_code_writer';
+import { ByteString } from '../../../src/util/byte_string';
 
 class ValueTestCase<T> {
   constructor(
@@ -108,6 +109,23 @@ const STRING_TEST_CASES: Array<ValueTestCase<string>> = [
   )
 ];
 
+const BYTES_TEST_CASES: Array<ValueTestCase<Uint8Array>> = [
+  new ValueTestCase(fromHex(''), '0001', 'fffe'),
+  new ValueTestCase(fromHex('00'), '00ff0001', 'ff00fffe'),
+  new ValueTestCase(fromHex('0000'), '00ff00ff0001', 'ff00ff00fffe'),
+  new ValueTestCase(fromHex('0001'), '00ff010001', 'ff00fefffe'),
+  new ValueTestCase(fromHex('0041'), '00ff410001', 'ff00befffe'),
+  new ValueTestCase(fromHex('00ff'), '00ffff000001', 'ff0000fffffe'),
+  new ValueTestCase(fromHex('01'), '010001', 'fefffe'),
+  new ValueTestCase(fromHex('0100'), '0100ff0001', 'feff00fffe'),
+  new ValueTestCase(fromHex('6f776c'), '6f776c0001', '908893fffe'),
+  new ValueTestCase(fromHex('ff'), 'ff000001', '00fffffe'),
+  new ValueTestCase(fromHex('ff00'), 'ff0000ff0001', '00ffff00fffe'),
+  new ValueTestCase(fromHex('ff01'), 'ff00010001', '00fffefffe'),
+  new ValueTestCase(fromHex('ffff'), 'ff00ff000001', '00ff00fffffe'),
+  new ValueTestCase(fromHex('ffffff'), 'ff00ff00ff000001', '00ff00ff00fffffe')
+];
+
 describe('Ordered Code Writer', () => {
   it('computes number of leading zeros', () => {
     for (let i = 0; i < 0xff; ++i) {
@@ -139,6 +157,34 @@ describe('Ordered Code Writer', () => {
     verifyOrdering(STRING_TEST_CASES);
   });
 
+  it('converts bytes to bits', () => {
+    verifyEncoding(BYTES_TEST_CASES);
+  });
+
+  it('orders bytes correctly', () => {
+    verifyOrdering(BYTES_TEST_CASES);
+  });
+
+  it('encodes infinity', () => {
+    const writer = new OrderedCodeWriter();
+    writer.writeInfinityAscending();
+    expect(writer.encodedBytes()).to.deep.equal(fromHex("ffff"));
+
+    writer.reset();
+    writer.writeInfinityDescending();
+    expect(writer.encodedBytes()).to.deep.equal(fromHex("0000"));
+  });
+
+  it('seeds bytes', () => {
+    const writer = new OrderedCodeWriter();
+    writer.seed(fromHex("01"));
+    writer.writeInfinityAscending();
+    writer.seed(fromHex("02"));
+    expect(writer.encodedBytes()).to.deep.equal(
+      fromHex("01ffff02")
+    );
+  });
+
   function verifyEncoding(testCases: Array<ValueTestCase<unknown>>): void {
     for (let i = 0; i < testCases.length; ++i) {
       const bytes = getBytes(testCases[i].val);
@@ -202,8 +248,9 @@ function getBytes(val: unknown): { asc: Uint8Array; desc: Uint8Array } {
   } else if (typeof val === 'string') {
     ascWriter.writeUtf8Ascending(val);
     descWriter.writeUtf8Descending(val);
-  } else {
-    throw new Error('Encoding not yet supported for ' + val);
+  } else if (val instanceof Uint8Array) {
+    ascWriter.writeBytesAscending(ByteString.fromUint8Array(val));
+    descWriter.writeBytesDescending(ByteString.fromUint8Array(val));
   }
   return { asc: ascWriter.encodedBytes(), desc: descWriter.encodedBytes() };
 }