ESP32-H21: Added full support
ESP32-H4: Added full support
ESP32-P4: Enabled USB-OTG in flasher stub
ESP32-P4: Added support for >16MB flash sizes in flasher stub
ESP32-S3: Added support for >16MB encrypted writes in flasher stub
chip_type_verification: Enabled in secure download mode, stopped using magic numbers
watchdog_reset: Added a new watchdog_reset option working even in USB modes
erase_region: Enabled erasing in ROM bootloader and secure download mode
Added information about the currently used USB mode during chip connection
image_info: Extended the app description info with new segments
esp_rfc2217: Improved the logger message format
Added the option to filter connections based on the serial number
hard_reset: Added support for custom hard reset sequence configuration
Added support for Python 3.13
espefuse: Added support for eFuses for ESP32-C5 ECO2
espefuse: Added support for eFuses for ESP32-C61 ECO3
espsecure: Improved error messages in encrypt_flash_data() and decrypt_flash_data()
espefuse: Added support for different eFuse table versions for ESP32-H2
espefuse: Added 3 bit for PSRAM_CAP efuse field
espefuse: Added API for getting block and wafer versions
espefuse: Added ADC calibration data for ESP32-C61, ESP32-C5, and ESP32-P4

stub_flasher: Fixed failing ESP32-C5 ECO2 flash writes
stub_flasher: Fixed USB-Serial/JTAG mode on ESP32-C5 ECO2 and ESP32-C61 ECO3
write_flash: Detect more cases of unresponsive flash, fixed failing flash_size check
write_flash: Skipped flash_size checks if we can't read flash size
espefuse: Fixed output messages in set_flash_voltage
espefuse: Corrected JTAG_SEL_ENABLE to GPIO34 strapping pin on ESP32-P4
ESP32-C5: Fixed bootloader address
ESP32-H21: Fixed eFuse base address
IntelHex: Do not use padding for merged IntelHex files
elf2image: Fixed for RAM app when SHA256 offset is not specified
elf2image: Fixed support for --flash-mmu-page-config for all chips
elf2image: Try to correct MMU page size if not specified, print correctly in error messages
tests: Expect the correct module name for Python 3.14 argparse
Fixed closing port when connection fails
image_info: Hidden missing app info based on IDF version
save_segment: Added segment length check, the same as the bootloader does
image_info: Prevented reading app description in invalid cases
esp_rfc2217: Fixed keyboard interrupt on Windows
detect_chip: Fixed to select the correct loader before further operations to avoid silent failures
usb_resets: Fixed resetting in USB-OTG and USB-Serial/JTAG modes

Thanks to @chromalock, @befeleme, and others for contributing to this release!

Results of checking the release against common anti-virus SW

The failures are probably false positives. You can mark esptool as safe in your anti-virus SW, or install esptool from source.

espressif/esptool v4.9.0 Version 4.9.0 on GitHub