--- title: Reverse Engineered Grill Controller Gets Open Firmware description: A hobbyist reverse engineered the control board of a Gravity 800 pellet grill after opening it for a minor wire repair, discovering an ESP-32 MCU, a 16-segment... canonical: https://daily.dev/posts/reverse-engineered-grill-controller-gets-open-firmware-hamrdatag twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Reverse Engineered Grill Controller Gets Open Firmware | daily.dev og:description: A hobbyist reverse engineered the control board of a Gravity 800 pellet grill after opening it for a minor wire repair, discovering an ESP-32 MCU, a 16-segment... og:url: https://daily.dev/posts/reverse-engineered-grill-controller-gets-open-firmware-hamrdatag og:image: https://api.daily.dev/og/posts/HAMrdATag.png og:image:alt: Reverse Engineered Grill Controller Gets Open Firmware og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Reverse Engineered Grill Controller Gets Open Firmware **[Hackaday](https://daily.dev/sources/hackaday)** · 2 min read · 0 upvotes · 0 comments ## Summary A hobbyist reverse engineered the control board of a Gravity 800 pellet grill after opening it for a minor wire repair, discovering an ESP-32 MCU, a 16-segment LCD, thermistor sensors, and a UART-connected analog frontend chip. Firmware was dumped over the labeled programming header using espflash and analyzed, revealing a quirky ADC correction routine. The effort resulted in a fully open-source replacement firmware package featuring OTA updates, PID-controlled temperature management, and a real-time web interface, now published on GitLab. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How was the firmware dumped from the Gravity 800 grill controller's ESP-32 chip? The firmware was dumped using the espflash utility connected to a neatly labeled programming header found on the control board. The board is built around an ESP-32 microcontroller, and once the header was located, extraction was straightforward, allowing analysis of the original firmware including an unusual ADC correction function. _daily.dev surfaces reverse-engineering write-ups like this for developers tinkering with embedded firmware._ ### What hardware is inside the Gravity 800 grill controller board? It uses an ESP-32 microcontroller alongside connectors for four thermistor temperature sensors, a lid open/close switch, a fan driver, a 16-segment LCD using a CS1621 display driver, a piezo buzzer, and physical input buttons. The thermistors and inputs connect through a separate 16-pin chip over a 9600 baud UART link, likely a cheap MCU acting as an analog frontend. _engineers piecing together unknown hardware often compare notes like these via daily.dev._ ## Similar posts on daily.dev - [Hacking A Cat Litter Box](https://daily.dev/posts/hacking-a-cat-litter-box-hd8ha5gmi) · Hackaday · 0 upvotes · 0 comments - [My Fan Worked Fine, So I Gave it WiFi](https://daily.dev/posts/my-fan-worked-fine-so-i-gave-it-wifi-fd4lzfzab) · Hacker News · 1 upvotes · 0 comments - [Someone turned a 60s Grundig Musikgerät radio into a networked speaker with an ESP32](https://daily.dev/posts/someone-turned-a-60s-grundig-musikger-t-radio-into-a-networked-speaker-with-an-esp32-l40fb3mm6) · XDA Developers · 0 upvotes · 0 comments - [Home Hardware, Part 1: My Control4 Revenge Arc](https://daily.dev/posts/home-hardware-part-1-my-control4-revenge-arc-jsj4sfar8) · Reid Burke · 0 upvotes · 0 comments --- Tags: [#embedded](https://daily.dev/tags/embedded), [#firmware](https://daily.dev/tags/firmware), [#hardware](https://daily.dev/tags/hardware), [#iot](https://daily.dev/tags/iot), [#reverse-engineering](https://daily.dev/tags/reverse-engineering) [View this post on daily.dev](https://daily.dev/posts/reverse-engineered-grill-controller-gets-open-firmware-hamrdatag) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Reverse Engineered Grill Controller Gets Open Firmware","url":"https://daily.dev/posts/reverse-engineered-grill-controller-gets-open-firmware-hamrdatag","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/reverse-engineered-grill-controller-gets-open-firmware-hamrdatag"},"datePublished":"2026-08-18T20:22:17.553Z","dateModified":"2026-10-15T02:24:28.280Z","description":"A hobbyist reverse engineered the control board of a Gravity 800 pellet grill after opening it for a minor wire repair, discovering an ESP-32 MCU, a 16-segment...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/80ff834417a992ee99100f4d82f68039?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/80ff834417a992ee99100f4d82f68039?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Hackaday","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Hackaday","logo":"https://media.daily.dev/image/upload/s--JhDfhy70--/f_auto,q_auto/v1767541814/logos/hackaday","url":"https://daily.dev/sources/hackaday"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/reverse-engineered-grill-controller-gets-open-firmware-hamrdatag","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"embedded,firmware,hardware,iot,reverse-engineering","timeRequired":"PT2M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Hackaday","item":"https://daily.dev/sources/hackaday"},{"@type":"ListItem","position":3,"name":"Reverse Engineered Grill Controller Gets Open Firmware"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/reverse-engineered-grill-controller-gets-open-firmware-hamrdatag#faq","mainEntity":[{"@type":"Question","name":"How was the firmware dumped from the Gravity 800 grill controller's ESP-32 chip?","acceptedAnswer":{"@type":"Answer","text":"The firmware was dumped using the espflash utility connected to a neatly labeled programming header found on the control board. 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