From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-x229.google.com (mail-qk0-x229.google.com [IPv6:2607:f8b0:400d:c09::229]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 3565721D18228 for ; Mon, 14 Aug 2017 13:47:31 -0700 (PDT) Received: by mail-qk0-x229.google.com with SMTP id d145so57255166qkc.2 for ; Mon, 14 Aug 2017 13:49:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=iZC+ilRP+a9aO332or1llreaPPnV3Mw3MVePAFeVUcw=; b=c/vnQkPSRoMccYdOSCAvLLG4ieJRN2WwNgher18U046cBupB/ozO6PdizGpHR5BNVy FrnFqp/4aeZuoL4RzNdzovBf/8dzOTEgolGahkosgFxedmyTugg2adlq4Q+axNMzP6gr lbuGbobceWiYJRj2koXinXWOd7W2edt2GeS7Oas8eNavztiaeNzjgs8S/Df+7Fi0Iw+n txd4B6vBj+sx/m8KuJjjGMW2WawXwE7H1UisqPapo+uLfDq9f3SbU7hyUrjeEUfhWsxj edzItTah2Go3vGCm3F2eAlMWflxymUKcfwCG3m+4WZEm1eZg9DTR8rC/d6UeJJ3181MS 6Ang== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=iZC+ilRP+a9aO332or1llreaPPnV3Mw3MVePAFeVUcw=; b=Uwlvd1ZFpxvM/F5y/m06ebKoVWGbYIf07B8C3crM9UgA0z7Sg+Bpb6vS4SGzHynOJq oCNXWxpewThFj0kOkf2kLVUrWJo8TvOyVtQORtaPhGEJAEqkAB/uRLToUu8wWOLxuQXY vqX+aKjupJhxlPF4D0w6Sly0hipJRbHZLIiBR90tU56Wqc71YJJN8uur8jioDtBLpyad +UH8yP6JmoTlEEPxVADLblHI3wh7AmyhPxNta76uVCENtcYU/6BIehiBy+95n9oKVyaX kBbpF1JVFdggylh4WW2fflgWcDZsy86NOGczUyUOKHMO4kevwHxSD03Phhhh10lawAa6 5NiQ== X-Gm-Message-State: AHYfb5g4XgefqIgOFDlnGU4fWucewNm1mcddDIuFs0AJNQaJVu7DirPQ DGQji5KZVy0K/QUJbcgT3jVMrB+AEw== X-Received: by 10.233.220.130 with SMTP id q124mr32548003qkf.284.1502743794596; Mon, 14 Aug 2017 13:49:54 -0700 (PDT) MIME-Version: 1.0 Received: by 10.200.8.125 with HTTP; Mon, 14 Aug 2017 13:49:14 -0700 (PDT) In-Reply-To: References: From: Igor Skochinsky Date: Mon, 14 Aug 2017 22:49:14 +0200 Message-ID: To: Rafael Machado Cc: "edk2-devel@lists.01.org" X-Content-Filtered-By: Mailman/MimeDel 2.1.22 Subject: Re: What Bios data is sent to the Bootloader/OS ? X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Aug 2017 20:47:31 -0000 Content-Type: text/plain; charset="UTF-8" Hi Rafael, It's certainly possible although not trivial. One possible approach is DUET which can emulate UEFI environment on top of the legacy BIOS. So you could have your legacy bootloader load DUET, which would in turn load and boot the UEFI-compatible OS. This page may be of use: http://www.rodsbooks.com/bios2uefi/index.html AFAIK GRUB already supports both BIOS and UEFI booting, so you may not have to do anything except set it up correctly. On Fri, Aug 11, 2017 at 3:00 PM, Rafael Machado < rafaelrodrigues.machado@gmail.com> wrote: > Hi everyone > > I have a question that probably some guys here can help. > The scenario I have, is that I need to create a OS image that must be able > to boot at a UEFI system (with no csm module), and at a legacy bios system. > My fist thought is that this is not possible. > > The first thing I see that is different is the what the memory map is > presented to the Bootloader/OS. At legacy bios the int15/0xE820 is used, > and at a UEFI bios the GetMemoryMap() from the boot service is used. Is my > understanding correct? > > Besides that. Is there any other change that could not make it possible to > create a single BootloaderLoader/OS image able to boot on a UEFI BIOS(with > no CSM) and on a Legacy Bios ? > > I would like to create a list or arguments to talk with my client that > requested this, in case this is really not possible. > > The OS in this case is Linux, and the bootloader is Grub or Syslinux. > > Thanks and Regards > Rafael R. Machado > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel > -- WBR, Igor