Re: FreeBSD EFI projects

From: Greg V <greg_at_unrelenting.technology>
Date: Wed, 19 Sep 2018 18:17:18 +0300
On Wed, Sep 19, 2018 at 6:06 PM, Rodney W. Grimes 
<freebsd-rwg_at_pdx.rh.CN85.dnsmgr.net> wrote:
>>  On Wed, Sep 19, 2018 at 5:34 PM, Rodney W. Grimes
>>  <freebsd-rwg_at_pdx.rh.CN85.dnsmgr.net> wrote:
>>  >>  On 9/18/18 4:11 AM, Greg V wrote:
>>  >>
>>  >>  >
>>  >>  > I can confirm that the kernel already worked fine when booted 
>> from
>>  >>  > 32-bit EFI.
>>  >>  >
>>  >>  > I booted an old Mac into HardenedBSD using a 32-bit-EFI build 
>> of
>>  >> GRUB2 :)
>>  >>
>>  >>
>>  >>  Was that a 64-bit version of FreeBSD? My understanding is the 
>> 32-bit
>>  >>  FreeBSD boots fine, but 64-bit needs work.
>>  >
>>  > You would be hard pressed to find a system with a 64 bit CPU that
>>  > could run 64 bit FreeBSD that had a 32 bit EFI implementation.
>> 
>>  Mac mini 2006 with a Core2Duo instead of the stock CoreDuo (and the
>>  2007 model's firmware flashed, but I don't think that impacts 
>> FreeBSD).
> 
> Yes, that is one of the catagories of rare, a EFI-32 bit system that
> was originally shipped with a 32 bit only CPU, that later got upgraded
> in the field with a 64 bit CPU, that still runs a EFI-32 bios.
> Are you sure the 2007 firmware is EFI32?  I would of thought
> since they upgraded the base system to a 64 bit CPU they would
> of shipped it with a EFI-64 bios.

The EFI firmware is technically 64 bit… but it only boots 32-bit 
binaries.

https://everymac.com/mac-answers/snow-leopard-mac-os-x-faq/mac-os-x-snow-leopard-64-bit-macs-64-bit-efi-boot-in-64-bit-mode.html

'Furthermore, it appears that although subsequently released MacBook, 
MacBook Air, and pre-"Mid-2010" Mac mini models all are equipped with 
"Core 2 Duo" 64-bit processors and 64-bit EFIs, Apple has blocked these 
"consumer-targeted" Macs from booting in 64-bit mode. iMac and MacBook 
Pro models released in 2007 with 64-bit EFIs seem to have been blocked 
as well.'

>>  And probably just the 2007 model as well :)
>> 
>>  Also, IIRC there were some Intel Atom tablets with 32-bit EFI.
> 
> Atom N2xx and Z5xx series Atom models cannot run x86-64

Atom Z3740 — "Instruction Set: 64-bit"
https://ark.intel.com/products/76759/Intel-Atom-Processor-Z3740-2M-Cache-up-to-1_86-GHz

The tablet in question: ASUS VivoTab Note 8 (M80TA)
https://www.asus.com/us/Tablets/ASUS_VivoTab_Note_8_M80TA/
Received on Wed Sep 19 2018 - 13:17:35 UTC

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