--- title: "Sony A7S III How to Update Firmware" canonical: "https://gadgetguides.org/sony-a7s-iii-how-to-update-firmware/" author: "Arian" published: "2026-09-05T14:45:24+00:00" modified: "2026-09-05T14:45:24+00:00" language: "en-US" site: "Gadget Guides" description: "If you've been searching for a clear guide on the Sony A7S III firmware update process, you've come to the right place. Updating the firmware is…" categories: "Cameras & Drones" attribution: "Gadget Guides (https://gadgetguides.org/)" --- # Sony A7S III How to Update Firmware If you've been searching for a clear guide on the Sony A7S III firmware update process, you've come to the right place. Updating the firmware is straightforward, but a single misstep can turn your expensive body into an expensive paperweight. This guide walks through the safe, correct way to do it. Manufacturer specs indicate the update file is typically 500 MB to 1 GB. The entire process takes about 10 to 15 minutes. As of 2026, the latest stable version brings important autofocus and stability improvements. Let's get your camera updated without any drama. ![Sony A7S III how to update firmware](https://gadgetguides.org/wp-content/uploads/2026/09/sony-a7s-iii-how-to-update-firmware-mtohvol0.webp) Image source: Web (Bing) / mcbaincamera.com (Web image (fair-use with source credit)) ## Quick Answer Download the firmware file from Sony's support site. Copy it to a formatted SD card. Insert the card into slot 1. Go to the menu and select Software Update. Confirm the update. The camera will restart. Do not interrupt the process. ## Why Getting This Firmware Update Right Actually Matters Firmware updates patch vulnerabilities, fix performance bugs, and improve lens compatibility. Sony's official support documentation states that improper updates can leave the camera in a non-functional state. That's a repair bill you don't want. Aggregate reviews from verified buyers report that the most common firmware issues involve a corrupt file or a power interruption during the update. The A7S III's internal flash memory is rewritten during the process. Any break in communication can corrupt the bootloader. This is an Expert YMYL topic for a reason. You're rewriting the camera's operating system, not installing an app. The stakes are high, but the process is simple when you follow the right steps. A little patience upfront saves a lot of headaches later. ## What You Need Before You Even Touch the Download Button Before you download anything, gather your tools. Each one is critical. ### The Essentials - **A fully charged NP-FZ100 battery.** The camera will not start the update if the battery is below 50% charge. Sony recommends 100% charge or using the AC-PW20 AC adapter. A dead battery mid-update is the most common cause of bricking. - **A compatible SD card.** Use a card that is Class 10 or UHS-I minimum. The card must be formatted in the camera using the Format function. This ensures the file system is FAT32 or exFAT. - **A computer with internet access.** You'll download the firmware file from the official [Sony support site](https://www.sony.com/support). Do not use third-party download links. - **The firmware file itself.** Make sure you download the exact file for the A7S III, not the A7S II or any other model. The file name usually includes the model number and version. - **A USB cable (optional).** The SD card method is the most reliable. We'll cover that method because it's the safest. ![Sony NP-FZ100 battery](https://gadgetguides.org/wp-content/uploads/2026/09/sony-np-fz100-battery-mtohvpx3.webp) Image source: Web (Bing) / amazon.com (Web image (fair-use with source credit)) ### One More Thing: Check Your Current Version Go to the menu. Navigate to Setup (the toolbox icon). Select Version. Write down the current firmware version. This confirms you actually need the update. If you're already on the latest version, you're done. ## The Step-by-Step Firmware Update Process (SD Card Method) This is the method Sony's official documentation recommends. It's the most stable because it doesn't rely on a USB connection that can drop. ### Step 1: Format the SD Card in the Camera Insert the SD card into Slot 1. Go to Menu > Setup > Format. This deletes everything on the card. It also ensures the file system is correct. Do not skip this step. ### Step 2: Download and Extract the Firmware File On your computer, go to the Sony support page for the A7S III. Download the latest firmware file. It will be a compressed folder (ZIP or EXE). Extract the folder. Inside, you will find a single file with a `.exe` or `.dmg` extension. This is the update file. Do not rename it. ### Step 3: Copy the File to the SD Card Root Copy the extracted firmware file to the root directory of the SD card. The root directory is the top level, not inside any folder. If you put it in a folder, the camera won't find it. ### Step 4: Insert the SD Card and Power On Insert the SD card into Slot 1 of the camera. Make sure the battery is fully charged. Turn the camera on. The camera will detect the update file. ### Step 5: Navigate to the Software Update Menu Go to Menu > Setup (toolbox icon) > Software Update. The camera will ask you to confirm. Select "OK." The camera will restart and begin the update process. A progress bar appears on the screen. ### Step 6: Wait. Do Not Touch Anything. The update takes 10 to 15 minutes. Do not turn off the camera. Do not remove the SD card. Do not open the battery door. The camera will restart again when the update is complete. ### Step 7: Verify the Update After the restart, go to Menu > Setup > Version. The new firmware version should be displayed. Your camera is now updated. ![Sony A7S III menu system](https://gadgetguides.org/wp-content/uploads/2026/09/sony-a7s-iii-menu-system-mtohvrev.webp) Image source: Web (Bing) / petapixel.com (Web image (fair-use with source credit)) ## Common Mistakes That Brick Cameras and How to Avoid Them Even experienced photographers make these errors. Knowing them in advance saves your camera. ### Using a Battery That's Not Fully Charged The camera checks battery level before starting. If it's below 50%, it won't even begin. If the battery dies during the update, the camera is bricked. Always charge to 100% or use the AC adapter. This is the single most important rule. ### Downloading the Wrong Firmware File Sony's support site lists firmware for multiple models. Double-check the model number. Downloading the file for the A7S II or A7 III will not work. The camera will reject it, but you could corrupt the file system. ### Interrupting the Process This includes turning off the camera, removing the SD card, or pressing buttons. The camera is writing to internal flash memory. Interrupting it can corrupt the bootloader. Set the camera down. Walk away for 15 minutes. ### Using a Corrupted SD Card If the card has errors, the firmware file may be partially written. Format the card in the camera before each update. This is non-negotiable. If you've had [card errors on other Sony bodies](https://gadgetguides.org/sony-a7-iv-card-error/), the same precautions apply here. ### Not Checking the Current Version First Some users try to install the same firmware twice. The camera will tell you it's already up to date, but it's a waste of time. Check the version first. If you're dealing with a [freezing issue on another camera](https://gadgetguides.org/gopro-hero10-black-freezing-problem/), the firmware update process is similar but the stakes are higher here. ### Removing the Card Before the Update Finishes The camera writes the new firmware to internal memory. If you remove the SD card before the process completes, the file system can corrupt. Leave it in place until the camera restarts. ### Using a USB Cable That's Not Rated for Data Some USB cables only charge. They don't transfer data. If you use the USB method and connect a charge-only cable, the camera won't recognize the computer. Use the cable that came with the camera or a known data-transfer cable. ## Expert Tips for a Smooth, Stress-Free Update These tips come from aggregate user feedback and Sony's support documentation. They save time and prevent panic. ### Use the AC Adapter If Possible The AC-PW20 adapter eliminates the risk of a dying battery. If you don't have one, charge the battery to 100% and do not use the camera before the update. Every minute of use drains the battery. ### Update in a Quiet, Stable Environment Don't update in a moving car or a crowded studio. Vibration or accidental button presses can interrupt the process. Put the camera on a flat surface. Walk away. ### Back Up Your Custom Settings The firmware update may reset your custom settings to factory defaults. Save them to the memory card using the camera's Save/Load Settings function. After the update, reload them. This saves you 20 minutes of menu diving. ### Check for Lens Compatibility Some firmware updates include lens-specific improvements. If you own a newer lens like the 24-70mm GM II or the 50mm F1.2 GM, check the release notes. The update may improve autofocus performance with those lenses. If you've had a [lens compatibility issue on another Sony body](https://gadgetguides.org/sony-a7r-v-lens-problem/), this update might resolve it. ### Keep Your Battery Healthy A battery that won't hold a full charge is a risk. If your NP-FZ100 is over a year old and shows reduced runtime, consider replacing it. A [failing power source](https://gadgetguides.org/sony-a7s-iii-battery-problem/) can cause the update to fail mid-process. Don't take the chance. ## What to Do If the Update Fails or Freezes Even with the best preparation, things can go wrong. Here's how to handle it. ### If the Progress Bar Stops Moving Wait five minutes. Some updates appear to freeze when they are actually writing large blocks of data. If the bar hasn't moved after five minutes, force the camera off by removing the battery. Wait 30 seconds. Reinsert the battery and try again. Start from the beginning with a fresh download. ### If the Camera Won't Turn On After an Update This is a bricked state. Remove the battery. Wait one minute. Reinsert the battery. Try to power on. If it still doesn't work, remove the SD card and try again. If the camera powers on without the card, the card is corrupted. Format it on a computer and try a fresh update. ### If the Camera Shows an Error Message Write down the error code. Common codes include "Update Failed" or "File Not Found." The first usually means a corrupted file. Re-download the firmware from the official site. The second means the file is not in the root directory. Move it to the root. ### When to Contact Sony Support If the camera still won't power on after trying the steps above, contact Sony's official support. Do not attempt to flash the firmware manually. Do not use third-party recovery tools. This voids the warranty. Sony's service centers have the tools to recover the bootloader. The repair is usually covered under warranty if the update was performed correctly. ## Frequently Asked Questions ### Can I update the firmware using a smartphone? No. The Sony A7S III does not support firmware updates via the Imaging Edge Mobile app. You must use a computer and an SD card or a USB cable. The camera's firmware update function only reads from the SD card or a direct computer connection. ### Do I need to remove the lens before updating? No, you can leave the lens attached. The update does not affect the lens mount or communication. However, if the update includes lens-specific firmware, the camera will prompt you to attach the lens before proceeding. ### Will the update erase my photos and videos? No. The firmware update only writes to the camera's internal memory, not the SD card. Your photos and videos on the card will remain intact. However, custom settings may be reset to factory defaults. ### How often does Sony release firmware updates for the A7S III? Sony releases updates infrequently, typically one to two per year. Major updates often coincide with new lens releases or feature additions. As of 2026, the latest version is a significant update with autofocus improvements. Check the Sony support site every few months. ### Can I downgrade to an older firmware version? Sony does not officially support downgrading. Once you update, you cannot roll back to an earlier version. This is a safety measure to prevent corruption. If you experience issues after an update, contact Sony support rather than attempting a downgrade. ### Is it safe to update if I'm using a third-party battery? Sony recommends using genuine NP-FZ100 batteries. Third-party batteries may not communicate the correct charge level to the camera. The camera could shut down unexpectedly during the update. Use a genuine Sony battery or the AC adapter.