diff --git a/src/platforms/GitHub/API.ts b/src/platforms/GitHub/API.ts
index 01e3fd4..d0a6657 100644
--- a/src/platforms/GitHub/API.ts
+++ b/src/platforms/GitHub/API.ts
@@ -110,14 +110,26 @@ export async function getPullPageDocument(
   userName: string,
   repoName: string,
   pullId: string, // not used
-  baseSHA: string,
-  headSHA: string,
 ): Promise<Document> {
+  // Response of this API contains view of few files but is not complete.
+  const filesDOM = await getDOM(
+    `https://${window.location.host}/${userName}/${repoName}/pull/${pullId}/files?_pjax=%23js-repo-pjax-container`,
+  )
+  const [baseSHA, headSHA] = [
+    filesDOM.querySelector('input[name="comparison_start_oid"]')?.getAttribute('value'),
+    filesDOM.querySelector('input[name="comparison_end_oid"]')?.getAttribute('value'),
+  ]
+  if (!baseSHA || !headSHA) throw new Error(`Cannot fetch SHA for comparison`)
+
+  // The SHA used to be retrieved from DOM of the pull page, but they can be unreliable if the PR has conflicts
   const search = new URLSearchParams(window.location.search)
   search.set('sha1', baseSHA)
   search.set('sha2', headSHA)
-  const url = `https://${window.location.host}/${userName}/${repoName}/diffs?${search}`
-  return new DOMParser().parseFromString(await (await fetch(url)).text(), 'text/html')
+  return await getDOM(`https://${window.location.host}/${userName}/${repoName}/diffs?${search}`)
+
+  async function getDOM(url: string) {
+    return new DOMParser().parseFromString(await (await fetch(url)).text(), 'text/html')
+  }
 }
 
 export async function getBlobData(
diff --git a/src/platforms/GitHub/DOMHelper.ts b/src/platforms/GitHub/DOMHelper.ts
index 1c5c014..3480871 100644
--- a/src/platforms/GitHub/DOMHelper.ts
+++ b/src/platforms/GitHub/DOMHelper.ts
@@ -24,29 +24,6 @@ export function getIssueTitle() {
   if (title && id) return `${id} ${title}`
 }
 
-export function getPullSHA() {
-  return $('#js-repo-pjax-container', e => {
-    const commentNodes: ChildNode[] = []
-    e.childNodes.forEach(node => {
-      if (node.nodeType === document.COMMENT_NODE) {
-        commentNodes.push(node)
-      }
-    })
-    let baseSHA, headSHA
-    for (const node of commentNodes) {
-      const matchBase = node.textContent?.match(/base sha1:.*?(\w{40})/)
-      if (matchBase) baseSHA = matchBase[1]
-      const matchHead = node.textContent?.match(/head sha1:.*?(\w{40})/)
-      if (matchHead) headSHA = matchHead[1]
-    }
-    if (baseSHA && headSHA)
-      return {
-        baseSHA,
-        headSHA,
-      }
-  })
-}
-
 export function getCurrentBranch() {
   const selectedBranchButtonSelector = [
     '.repository-content #branch-select-menu summary',
diff --git a/src/platforms/GitHub/index.ts b/src/platforms/GitHub/index.ts
index a9eda0b..af82cdb 100644
--- a/src/platforms/GitHub/index.ts
+++ b/src/platforms/GitHub/index.ts
@@ -1,4 +1,3 @@
-import { raiseError } from 'analytics'
 import { GITHUB_OAUTH } from 'env'
 import { Base64 } from 'js-base64'
 import { platform } from 'platforms'
@@ -254,14 +253,7 @@ async function createPullFileResolver(userName: string, repoName: string, pullId
   if (URLHelper.parse().path[1] === 'files') {
     doc = document
   } else {
-    const shas = DOMHelper.getPullSHA()
-    if (!shas) {
-      raiseError(new Error(`Cannot resolve sha from DOM`))
-      doc = document
-      // fallback, at least not throw error
-    } else {
-      doc = await API.getPullPageDocument(userName, repoName, pullId, shas.baseSHA, shas.headSHA)
-    }
+    doc = await API.getPullPageDocument(userName, repoName, pullId)
   }
 
   return (path: string) => {