Comment 3 for bug 543177

I have done a short test:

1. If the printer is up and running with loaded firmware, discovery works perfectly, like with a printer with built-in firmware.

2. If you load the firmware, for example by turning it on, and probe the printer during firmware transfer, it once does not get detected and second, the firmware gets corrupted and so the printer does not get detected after the firmware transfer, too. You have to turn it off and on again and then to wait for the firmware transfer to complete, so that 1. applies.

3. You should not install the firmware for both foo2zjs and HPLIP, either you run "sudo hp-plugin" (will be started automatically under Lucid) or "sudo getweb 1020", never both. If you do both, two copies of the firmware are loaded into the printer simultaneously, which also corrupts the firmware. To solve this, remove one copy, for example via "sudo rm /usr/share/foo2zjs/firmware/*". Then turn off and turn on the printer again, wait for the firmware transfer to complete, and 1. will apply. It is no problem if the firmware got installed via HPLIP and the driver if foo2zjs or vice versa.

One would need a way to make the printer probe wait if the printer receives firmware. To protect the firmware transfer against the automatic probe which happens directly after turning on the printer HPLIP's udev script for loading the firmware has a three-second delay.