Had copied something wrong.
But now I get:
C:\tools>fastboot flash zip rom.zip
sending 'zip' (529282 KB)... OKAY [ 83.727s]
writing 'zip'... INFOzip header checking...
INFOzip info parsing...
FAILED (remote: 99 unknown fail)
finished. total time: 87.036s
But now I get:
C:\tools>fastboot flash zip rom.zip
sending 'zip' (529282 KB)... OKAY [ 83.727s]
writing 'zip'... INFOzip header checking...
INFOzip info parsing...
FAILED (remote: 99 unknown fail)
finished. total time: 87.036s