diff --git a/src/activities/boot_sleep/SleepActivity.cpp b/src/activities/boot_sleep/SleepActivity.cpp
index 93622a03..1b59719b 100644
--- a/src/activities/boot_sleep/SleepActivity.cpp
+++ b/src/activities/boot_sleep/SleepActivity.cpp
@@ -155,7 +155,10 @@ std::string SleepActivity::getBookOverlayText(const std::string& bookPath) const
       if (Storage.openFileForRead("SLP", xtc.getCachePath() + "/progress.bin", f)) {
         uint8_t data[4];
         if (f.read(data, 4) == 4) {
-          uint32_t currentPage = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+          uint32_t currentPage = static_cast<uint32_t>(data[0]) |
+                                 (static_cast<uint32_t>(data[1]) << 8) |
+                                 (static_cast<uint32_t>(data[2]) << 16) |
+                                 (static_cast<uint32_t>(data[3]) << 24);
           uint32_t totalPages = xtc.getPageCount();
           float progress = xtc.calculateProgress(currentPage) * 100.0f;
           char progressStr[32];