ATS Mini firmware on the LilyGO T-Embed SI4732: a battery AM/FM/SW broadcast receiver

The UK government's Be Ready checklist puts a battery or wind-up FM radio in the household emergency kit, for updates during outages, with the frequencies of your news stations written down. The LilyGO T-Embed SI4732 is a finished, battery-powered device that can fill that slot: an ESP32-S3 (16 MB flash, 8 MB PSRAM) with a Si4732-A10 AM/FM/SW/LW/RDS receiver chip, a 1.9-inch ST7789V screen (170 × 320), a rotary encoder, a speaker and a 900 mAh 702550 battery. There's nothing to build: this guide is about flashing better firmware onto the stock device. ATS Mini is MIT-licensed community firmware for Si4732 receivers, maintained by max-arnold and built on work by Volos Projects, PU2CLR (Ricardo), Ralph Xavier, Goshante and G8PTN (Dave). Its changelog lists "Experimental support for LILYGO T-Embed SI4732" from v2.34, as the lilygo-t-embed firmware variant. The flash docs warn that this variant only works on the T-Embed SI4732 receiver, and that flashing a different firmware can damage the receiver. This is a receive-only broadcast receiver for AM, FM, shortwave and longwave stations. Its bands stop at 108 MHz (ATS Mini manual), and NOAA Weather Radio broadcasts on 162.400-162.550 MHz, so it is not a weather-alert or NOAA radio. Power caveats, before you rely on it: - The T-Embed SI4732 has no hard power switch. In discussion #166 the ATS Mini maintainer writes that in sleep mode the circuit "drains the battery in a couple of days". - The ATS Mini hardware page says it is "highly recommended to do a little hardware mod and install a physical power switch (without it you won't be able to switch the receiver off after you flash the ATS Mini firmware)". In ATS Mini, a short press on the Off Timer menu option puts it into deep sleep, and the reset button restarts it. - Because sleep drains the battery, charge it before you put it away and check it regularly, so it isn't flat when you need it. The hardware page also notes there's no headphone jack, the speaker is on top, and the SI4732 board has separate FM and AM antenna connectors. Alternative firmware: anducampu's ESP32-S3-LILYGO-T-EMBED-SI4732 (GPL-3.0) is a separate AM/FM/SW/LW sketch with SSB and remote control (CAT) over USB serial or Wi-Fi.