RE: Cannot boot from dual bios/uefi boot CD

[John Frankish]

>>>>> Yes, I have reproduced it now. The reason is, grub-mkrescue adds 
>>>>> commands to load all partition drivers to embedded config and if 
>>>>> some of them (or may be the last one) is missing it sets error indication.
>>>>> Later grub misinterprets this error indication when loading normal 
>>>>> module; loading it manually succeeds (insmod normal; normal).
>>>> If I add code to reset error indication before trying to load normal it 
>>>> works.
>>>>>
>>>>> So it still works for your purposes, albeit with manual workaround 
>>>>> :)
>>>>
>>>> Indeed - but I could hardly make it available to others like this :)
>>>>
>>>>
>>> For the record - it should be fixed in current GIT.
>>> If you have chance to retest it would be good.
>>>
>> Thanks for the update.
>>
>> The dual boot cd/iso I was working on used isolinux for legacy boot and 
>> grub2 for uefi boot.
>>
>> What I would like to do is to use grub2 for both legacy and uefi boot by 
>> embedding the various
>> grub modules as before (which would also test your fix).
>>
>> Is this (grub2 dual boot cd/iso) possible?
>
> Of course. This is what grub-mkrescue does.
>
>> Is there an explanation somewhere?
>>
>
> I though we have been there already last time, not?

OK, I understand that what is now fixed in git is that if I use grub-mkrescue 
to make an iso and then remove the unneeded modules from i386-pc/ and 
x86_64_efi/, the iso will still boot - is that correct?

I can see that grub-mkrescue makes an efi.img that contains 347kb of 
bootx64.efi, but is there a way to know which modules this contains?

Similarly, there must be an equivalent legacy-bios img file 
(cdboot.img/core.img?) , but where is it in the iso, is it accessible and which 
modules does it contain?

..the reason I ask this is so I know which modules I can remove from i386-pc/ 
and x86_64_efi/ - I could always make a new efi.img, but I don't know if it is 
possible to make a new cdboot.img/core.img?

Happy Christmas :)