If you have a Wemos/LOLIN S3 MINI PRO board, you might find that firmware images don’t flash so well. That’s because the ESP32-S3FH4R2 has 4 MB of flash storage, and most ESP32-S3 boards have 8 MB.
glenn20/mp-image-tool-esp32 might be your new friend:
mp-image-tool-esp32 -f 4M --resize vfs=2M ESP32_GENERIC_S3-20250415-v1.25.0.bin
This trims down a standard MicroPython ESP32-S3 firmware from a 4 MB filesystem partition down to 2 MB, and sets the overall flash size to 4 MB. Upload that to your board, and all will be well.
Alternatively, v1.26 supports “4MiB and larger” flash chips. I have confirmed that ESP32_GENERIC_S3-20250724-v1.26.0-preview.bin works as expected:
$ mpremote a1 run boardstats.py
Board : Generic ESP32S3 module with ESP32S3
Frequency : 160 MHz
Free Memory : 2061232
File storage: 2036 / 2048 K
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