Error "Invalid typed array length" when writing image

Trying to write a legacy MacOS installer image from a DMG file to a CF card hooked up via USB, I get this error and the writing is cancelled

RangeError: Invalid typed array length
at Buffer.Uint8Array (native)
at FastBuffer (buffer.js:11:5)
at createUnsafeBuffer (buffer.js:37:10)
at Function.Buffer.alloc (buffer.js:141:12)
at ReadStream._read (/Applications/3rd-party/balenaEtcher.app/Contents/Resources/app.asar/node_modules/udif/lib/readstream.js:128:25)
at ReadStream._read (/Applications/3rd-party/balenaEtcher.app/Contents/Resources/app.asar/node_modules/udif/lib/readstream.js:118:21)
at ReadStream.Readable.read (/Applications/3rd-party/balenaEtcher.app/Contents/Resources/app.asar/node_modules/readable-stream/lib/stream_readable.js:436:10)
at maybeReadMore
(/Applications/3rd-party/balenaEtcher.app/Contents/Resources/app.asar/node_modules/readable-stream/lib/_stream_readable.js:518:12)
at _combinedTickCallback (internal/process/next_tick.js:80:11)
at process._tickCallback (internal/process/next_tick.js:104:9)

balenaEtcher is 1.4.9 on macOS 10.14.1

I managed to write my image by converting it to a “CD/DVD master” in Disk Utility and etching that instead.

Even so, might want to clean up the weird internal error on “strange” disk images