diff --git a/source/fs/WUXFileWriter.cpp b/source/fs/WUXFileWriter.cpp
index 15482c2..e15a121 100644
--- a/source/fs/WUXFileWriter.cpp
+++ b/source/fs/WUXFileWriter.cpp
@@ -76,7 +76,7 @@ int32_t WUXFileWriter::writeSector(const uint8_t *buffer, uint32_t numberOfSecto
             indexTable[this->currentSector] = swap_uint32(this->writtenSector);
             hashMap[hashOut]                = writtenSector;
             if (isOpen()) {
-                if (!write((uint8_t *) addr, this->sectorSize)) {
+                if (write((uint8_t *) addr, this->sectorSize) != this->sectorSize) {
                     DEBUG_FUNCTION_LINE_ERR("Write failed");
                     return -1;
                 }
diff --git a/source/fs/WriteOnlyFileWithCache.cpp b/source/fs/WriteOnlyFileWithCache.cpp
index 4379c7e..62ecb3f 100644
--- a/source/fs/WriteOnlyFileWithCache.cpp
+++ b/source/fs/WriteOnlyFileWithCache.cpp
@@ -45,7 +45,7 @@ WriteOnlyFileWithCache::~WriteOnlyFileWithCache() {
 bool WriteOnlyFileWithCache::flush() {
     if (this->writeBufferPos > 0) {
         int32_t res = CFile::write(static_cast<const uint8_t *>(this->writeBuffer), this->writeBufferPos);
-        if (res < 0) {
+        if (res != this->writeBufferPos) {
             DEBUG_FUNCTION_LINE_ERR("Failed to flush cache, write failed: %d (expected %d)", res, this->writeBufferPos);
             return false;
         }