[aq1018]

• Reset to the app answers Unsupported when the app region's first word is erased, as it does while Updating; a system-flash bootloader hands off by boot mode without checking the app, so a blank chip jumped into erased flash and hung until a power cycle
• Storage::app_present (provided, length-checked) shared with validate_app's no-CRC check; ch32 overrides it without the length test
• +4 to +8 B .text per boot bin; V003 heaviest keeps 34 B of system flash
• CLI refusal message covers both causes
• tinyboot-core 0.6.2, tinyboot-ch32 0.7.1, tinyboot 0.5.2; CHANGELOG, protocol README and remote-updates table