diff --git a/install.cpp b/install.cpp
index 209300e..d8372e2 100644
--- a/install.cpp
+++ b/install.cpp
@@ -31,7 +31,6 @@
 #include <vector>
 
 #include <android-base/file.h>
-#include <android-base/logging.h>
 #include <android-base/parseint.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
@@ -514,13 +513,6 @@
     modified_flash = true;
     auto start = std::chrono::system_clock::now();
 
-    FILE* install_log = fopen_path(install_file, "w");
-    if (install_log) {
-        fputs(path, install_log);
-        fputc('\n', install_log);
-    } else {
-        LOGE("failed to open last_install: %s\n", strerror(errno));
-    }
     int result;
     std::vector<std::string> log_buffer;
     if (setup_install_mounts() != 0) {
@@ -529,33 +521,40 @@
     } else {
         result = really_install_package(path, wipe_cache, needs_mount, log_buffer, retry_count);
     }
-    if (install_log != nullptr) {
-        fputc(result == INSTALL_SUCCESS ? '1' : '0', install_log);
-        fputc('\n', install_log);
-        std::chrono::duration<double> duration = std::chrono::system_clock::now() - start;
-        int count = static_cast<int>(duration.count());
-        // Report the time spent to apply OTA update in seconds.
-        fprintf(install_log, "time_total: %d\n", count);
-        fprintf(install_log, "retry: %d\n", retry_count);
 
-        for (const auto& s : log_buffer) {
-            fprintf(install_log, "%s\n", s.c_str());
-        }
+    // Measure the time spent to apply OTA update in seconds.
+    std::chrono::duration<double> duration = std::chrono::system_clock::now() - start;
+    int time_total = static_cast<int>(duration.count());
 
-        if (ensure_path_mounted(UNCRYPT_STATUS) != 0) {
-            LOG(WARNING) << "Can't mount " << UNCRYPT_STATUS;
+    if (ensure_path_mounted(UNCRYPT_STATUS) != 0) {
+        LOGW("Can't mount %s\n", UNCRYPT_STATUS);
+    } else {
+        std::string uncrypt_status;
+        if (!android::base::ReadFileToString(UNCRYPT_STATUS, &uncrypt_status)) {
+            LOGW("failed to read uncrypt status: %s\n", strerror(errno));
+        } else if (!android::base::StartsWith(uncrypt_status, "uncrypt_time:")) {
+            LOGW("corrupted uncrypt_status: %s: %s\n", uncrypt_status.c_str(), strerror(errno));
         } else {
-            std::string uncrypt_status;
-            if (!android::base::ReadFileToString(UNCRYPT_STATUS, &uncrypt_status)) {
-                PLOG(WARNING) << "failed to read uncrypt status";
-            } else if (!android::base::StartsWith(uncrypt_status, "uncrypt_time:")) {
-                PLOG(WARNING) << "corrupted uncrypt_status: " << uncrypt_status;
-            } else {
-                fprintf(install_log, "%s\n", android::base::Trim(uncrypt_status).c_str());
-            }
+            log_buffer.push_back(android::base::Trim(uncrypt_status));
         }
-        fclose(install_log);
     }
+
+    // The first two lines need to be the package name and install result.
+    std::vector<std::string> log_header = {
+        path,
+        result == INSTALL_SUCCESS ? "1" : "0",
+        "time_total: " + std::to_string(time_total),
+        "retry: " + std::to_string(retry_count),
+    };
+    std::string log_content = android::base::Join(log_header, "\n") + "\n" +
+            android::base::Join(log_buffer, "\n");
+    if (!android::base::WriteStringToFile(log_content, install_file)) {
+        LOGE("failed to write %s: %s\n", install_file, strerror(errno));
+    }
+
+    // Write a copy into last_log.
+    LOGI("%s\n", log_content.c_str());
+
     return result;
 }
 
diff --git a/recovery.cpp b/recovery.cpp
index ccb2d22..0f0b978 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -1429,15 +1429,18 @@
 }
 
 static void log_failure_code(ErrorCode code, const char *update_package) {
-    FILE* install_log = fopen_path(TEMPORARY_INSTALL_FILE, "w");
-    if (install_log != nullptr) {
-        fprintf(install_log, "%s\n", update_package);
-        fprintf(install_log, "0\n");
-        fprintf(install_log, "error: %d\n", code);
-        fclose(install_log);
-    } else {
-        LOGE("failed to open last_install: %s\n", strerror(errno));
+    std::vector<std::string> log_buffer = {
+        update_package,
+        "0",  // install result
+        "error: " + std::to_string(code),
+    };
+    std::string log_content = android::base::Join(log_buffer, "\n");
+    if (!android::base::WriteStringToFile(log_content, TEMPORARY_INSTALL_FILE)) {
+        LOGE("failed to write %s: %s\n", TEMPORARY_INSTALL_FILE, strerror(errno));
     }
+
+    // Also write the info into last_log.
+    LOGI("%s\n", log_content.c_str());
 }
 
 static ssize_t logbasename(