Thanks Colin, Steve, Val and Denise,
I just installed ubuntu 1204 using the precise daily images proposed by Steve (#88) with the patched kernel (3.5.0-22) from Colin (#74) on a samsung 530u3c-a0ede in the normal way as described by Denise (#120) using the uefi setting at boot suggested by Val (#119) in a dual boot environment with win8.
1. First I put the precise daily image precise-desktop-amd64.iso from http://cdimage.ubuntu.com/precise/daily-live/current/ on a usb flash drive using Start-up disk creator on a machine running ubuntu 1210 and checking that it booted (on a different computer) and that the linux image had Colin's patches (looking at the changelog from within synaptic).
2. On the smasung laptop I upgraded the bios to version p05abh, set fast bios mode under the advanced tab to disabled and also secure boot under the boot tab. Disabling secure boot revealed an option for os mode selection which I set to 'uefi os' (not 'uefi os and cmos'). Under the boot tab I also moved the usb hdd boot option to the top.
3. I booted from the usb flash drive and chose install ubuntu using the default settings for installation with win8, letting ubuntu choose the partitions. I did not touch any buttons on the computer, and left the flash drive in the machine.
4. Still with the flash drive present I rebooted into ubuntu, all worked, including the sound and brightness function buttons. Only now I unmounted the flash drive and removed it. I installed synaptic to check the linux image in the changelog for Colin's changes.
5. Reboot into win8 did not work (see also Val #114). I got this:
'error: can't find command `drivemap`.
error: invalid EFI file path.
Press any key to continue...'
This error has been reported here
and a fix is given in post #18 there (suggested here by Val #114).
6. Now both booting win8 and booting work.
I got this computer yesterday, following this bug since last week, I was really afraid to destroy it, but Colin's and Steve's reassurances (sort of) and the trials of Val and Denise made me risk it. Thanks to you a lot. I guess this has been verified on 3 samsung laptops now: 530u3c, 532u3c, 700z5c.
Incidentally, the device name ubuntu chose during the installation was 530u3c-530u4c-532u3c. This might suggest that it might work for 540u4c also.
A real validation can only be done on a laptop that was bricked before, even though circumstantial evidence suggests that 'samsung-laptop' might be the culprit (see also https://bugzilla.kernel.org/show_bug.cgi?id=47121#c20).