Hi angus, Firstly both of those will work, but you will need to have a wifi network available to connect to as they need the internet to get to your installation media which in those cases comes from apple.
As for your SD card, I’d try these 2 options. On start up if you can see enough Hold down Just the Option key and kleep holding it until you hear the chime This will give you all available bootable devices currently available on your machine, Including your SD card. Once this screen shows the devices, You tab to the SD card and hit enter then just wait for it to start up on to the installer, It will either show the language to run as or the utilities. Then follow your prompts as required. Or even easier and not needing sight, Start the iMac up as normal, Go in to system preferrences Scrole down till you find the start up disk, Open this, Unlock if you need to, Find the SD card bootable disk if it’s there vo keys plus space bar to select it, Then select the restart button which you need to do twice and wait for the machine to boot from the sd card and as abopve follow the prompts. If you are going to use the command r or command shift r options then you wont need the SD card as those both use the interwebness to install MacOS. Or even better and as tim said, Just run the installer and it will install over your current system which means you wont have to worry about backing up and recovering everything. Hope that helps. From: macvisionaries@googlegroups.com <macvisionaries@googlegroups.com> On Behalf Of Angus MacKinnon Sent: Friday, 1 November 2019 12:37 PM To: MacVisionaries <macvisionaries@googlegroups.com> Subject: Re: Reformating iMac and Installing Catalina Simon Thank you. Is it CMD+R or Shift+CMD+R? And I shotdown the iMac and Cold Boot with the SD Card in the slot. What option should I choose? Angus MacKinnon, Personalism Student Charles Péguy said, “The revolution is moral or not at all” -- The following information is important for all members of the Mac Visionaries list. If you have any questions or concerns about the running of this list, or if you feel that a member's post is inappropriate, please contact the owners or moderators directly rather than posting on the list itself. Your Mac Visionaries list moderator is Mark Taylor. You can reach mark at: mk...@ucla.edu<mailto:mk...@ucla.edu> and your owner is Cara Quinn - you can reach Cara at caraqu...@caraquinn.com<mailto:caraqu...@caraquinn.com> The archives for this list can be searched at: http://www.mail-archive.com/macvisionaries@googlegroups.com/ --- You received this message because you are subscribed to the Google Groups "MacVisionaries" group. To unsubscribe from this group and stop receiving emails from it, send an email to macvisionaries+unsubscr...@googlegroups.com<mailto:macvisionaries+unsubscr...@googlegroups.com>. To view this discussion on the web visit https://groups.google.com/d/msgid/macvisionaries/1417FBEE-22DF-45FA-B31E-9BA190A58DEC%40gmail.com<https://groups.google.com/d/msgid/macvisionaries/1417FBEE-22DF-45FA-B31E-9BA190A58DEC%40gmail.com?utm_medium=email&utm_source=footer>. -- The following information is important for all members of the Mac Visionaries list. If you have any questions or concerns about the running of this list, or if you feel that a member's post is inappropriate, please contact the owners or moderators directly rather than posting on the list itself. Your Mac Visionaries list moderator is Mark Taylor. You can reach mark at: mk...@ucla.edu and your owner is Cara Quinn - you can reach Cara at caraqu...@caraquinn.com The archives for this list can be searched at: http://www.mail-archive.com/macvisionaries@googlegroups.com/ --- You received this message because you are subscribed to the Google Groups "MacVisionaries" group. To unsubscribe from this group and stop receiving emails from it, send an email to macvisionaries+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/macvisionaries/SY2PR01MB298794222D4CA64523A41CBB8A630%40SY2PR01MB2987.ausprd01.prod.outlook.com.
