cleanup install docu

admin-guide/deployment/basic_installation.md

@@ -18,6 +18,19 @@ The default way to interact with sysdb is to use [bob](https://git.psi.ch/linux-
 
 Altenatively you many have on your workstation a local copy of `bob`. This can be done by installing the RPM from the pli-misc repository - https://repos.psi.ch/rhel8/latest/pli-misc/ or by installing the Python package manually. More details regaring `bob` can be found [here](https://git.psi.ch/linux-infra/bob).
 
+## Hardware/VM Requirements
+
+For hardware based system please check the Hardware compatibility page for
+- [RHEL8](rhel8/hardware_compatibility.md)
+- [RHEL9](rhel9/hardware_compatibility.md)
+
+In any case these are the **minimal** system requirements:
+- RHEL8
+   - RAM: 4GB
+   - Harddisk: 33GB
+- RHEL9
+   - RAM: 4GB
+   - Harddisk: 64GB
 
 ## Sysdb Configuration
 
@@ -92,3 +105,27 @@ bob node set-attr $FQDN system_disk=md126
 ```
 
 It is also possible to customize the partitioning by using the `partitions` attribute on sysdb. See https://git.psi.ch/linux-infra/bob for more details.
+
+
+##  BIOS / UEFI Boot
+
+All systems should use UEFI boot for booting! BIOS based boot should only be used where UEFI is not an option.
+
+### UEFI
+
+__NOTE:__ After the installation the boot order will be changed to localboot again! So if you reinstall make sure that you re-set the bootorder via the efi menu or the commandline: https://linux.die.net/man/8/efibootmgr
+
+```bash
+[root@lx-test-02 ~]# efibootmgr
+BootCurrent: 0004
+BootOrder: 0004,0002,0000,0001,0003
+Boot0000* EFI Virtual disk (0.0)
+Boot0001* EFI VMware Virtual SATA CDROM Drive (0.0)
+Boot0002* EFI Network
+Boot0003* EFI Internal Shell (Unsupported option)
+Boot0004* Red Hat Enterprise Linux
+
+[root@lx-test-02 ~]# efibootmgr --bootorder 2,4,0,1,3
+```
+
+(there is no need to have the leading 000 )