The output of "fdisk -l" is below
Disk /dev/sda: 238.47 GiB, 256060514304 bytes, 500118192 sectors
Disk model: Micron_1100_MTFD
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 5A2D8A72-2B6D-429C-BF7C-C8972A97B3E4

Device Start End Sectors Size Type
/dev/sda1 2048 329727 327680 160M EFI System
/dev/sda2 329728 13961215 13631488 6.5G Linux swap
/dev/sda3 13961216 500118158 486156943 231.8G Linux filesystem


Disk /dev/sdb: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: WDC WD10SPZX-08Z
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: D776A9D6-B003-40DB-88E4-5FADAD850172

Device Start End Sectors Size Type
/dev/sdb1 2048 1953523711 1953521664 931.5G Linux filesystem


Disk /dev/sdc: 2.73 TiB, 3000558944256 bytes, 5860466688 sectors
Disk model: Elements 25A1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: B4CAA800-DC73-4A4E-B4C8-4984964A58F0

Device Start End Sectors Size Type
/dev/sdc1 2048 5860464639 5860462592 2.7T Microsoft basic data

This is what I have had on this since day one.....................

and finally the output (ls -al) of the /boot/efi partition that is /dev/sda1 (FAT32)
bash-5.1# pwd
/
bash-5.1# cd boot/efi
bash-5.1# ls -al
total 5
drwxr-xr-x 3 root root 512 Dec 31 1969 .
drwxr-xr-x 5 root root 4096 Nov 30 11:46 ..
drwxr-xr-x 3 root root 512 Jun 1 2021 EFI
bash-5.1# cd EFI
bash-5.1# ls -al
total 2
drwxr-xr-x 3 root root 512 Jun 1 2021 .
drwxr-xr-x 3 root root 512 Dec 31 1969 ..
drwxr-xr-x 2 root root 512 Nov 30 12:56 Slackware
bash-5.1# cd Slackware
bash-5.1# ls -al
total 24511
drwxr-xr-x 2 root root 512 Nov 30 12:56 .
drwxr-xr-x 3 root root 512 Jun 1 2021 ..
-rwxr-xr-x 1 root root 160 Nov 30 11:46 elilo.conf
-rwxr-xr-x 1 root root 238531 Jun 12 2018 elilo.efi
-rwxr-xr-x 1 root root 9320771 Nov 30 11:46 initrd.gz
-rwxr-xr-x 1 root root 7768960 Nov 27 14:58 vmlinuz
-rwxr-xr-x 1 root root 7768960 Nov 27 14:58 vmlinuz-generic-5.15.80
bash-5.1#

I did try the gdisk /dev/sda1 but that does not appear any different than in the past.

Output with efibootmgr ?

The output of "fdisk -l" is immediately below, and this looks normal and no different than previously viewed
======================
Disk /dev/sda: 238.47 GiB, 256060514304 bytes, 500118192 sectors
Disk model: Micron_1100_MTFD
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 5A2D8A72-2B6D-429C-BF7C-C8972A97B3E4

Device Start End Sectors Size Type
/dev/sda1 2048 329727 327680 160M EFI System
/dev/sda2 329728 13961215 13631488 6.5G Linux swap
/dev/sda3 13961216 500118158 486156943 231.8G Linux filesystem


Disk /dev/sdb: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: WDC WD10SPZX-08Z
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: D776A9D6-B003-40DB-88E4-5FADAD850172

Device Start End Sectors Size Type
/dev/sdb1 2048 1953523711 1953521664 931.5G Linux filesystem


Disk /dev/sdc: 2.73 TiB, 3000558944256 bytes, 5860466688 sectors
Disk model: Elements 25A1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: B4CAA800-DC73-4A4E-B4C8-4984964A58F0

Device Start End Sectors Size Type
/dev/sdc1 2048 5860464639 5860462592 2.7T Microsoft basic data
=============================================
and this is the directory tree from /dev/sda1 which is the EF00 partition on this laptop

=============================================
bash-5.1# pwd
/
bash-5.1# cd boot/efi
bash-5.1# ls -al
total 5
drwxr-xr-x 3 root root 512 Dec 31 1969 .
drwxr-xr-x 5 root root 4096 Nov 30 11:46 ..
drwxr-xr-x 3 root root 512 Jun 1 2021 EFI
bash-5.1# cd EFI
bash-5.1# ls -al
total 2
drwxr-xr-x 3 root root 512 Jun 1 2021 .
drwxr-xr-x 3 root root 512 Dec 31 1969 ..
drwxr-xr-x 2 root root 512 Nov 30 12:56 Slackware
bash-5.1# cd Slackware
bash-5.1# ls -al
total 24511
drwxr-xr-x 2 root root 512 Nov 30 12:56 .
drwxr-xr-x 3 root root 512 Jun 1 2021 ..
-rwxr-xr-x 1 root root 160 Nov 30 11:46 elilo.conf
-rwxr-xr-x 1 root root 238531 Jun 12 2018 elilo.efi
-rwxr-xr-x 1 root root 9320771 Nov 30 11:46 initrd.gz
-rwxr-xr-x 1 root root 7768960 Nov 27 14:58 vmlinuz
-rwxr-xr-x 1 root root 7768960 Nov 27 14:58 vmlinuz-generic-5.15.80
bash-5.1#
==========================================

The output of gdisk /dev/sda1 using the "p" also looks the same as it has in the past.

=======================================
Thanks for the comments.

Sorry about that I reposted the wrong file - this is the output of efibootmgr
====================

bash-5.1# efibootmgr
BootCurrent: 0002
Timeout: 10 seconds
BootOrder: 0002,0000,0001,9999
Boot0000* Slackware
HD(1,GPT,14f5c5da-30c9-e640-9431-86e6a606c4ed,0x800,0x50000)/File(\EFI\Slackware
\elilo.efi)
Boot0001* Windows Boot Manager
HD(1,GPT,af1c99a6-a363-4762-95fe-ec55c77137ab,0x800,0x82000)/File(\EFI\Microsoft
\Boot\bootmgfw.efi)WINDOWS.........x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5
.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.4.7.9.5.}....................
Boot0002* Internal CD/DVD ROM Drive (UEFI)
PciRoot(0x0)/Pci(0x8,0x2)/Pci(0x0,0x1)/Sata(1,65535,0)/CDROM(1,0x2ed,0xb40)..BO
Boot9999* USB Drive (UEFI) PciRoot(0x0)/Pci(0x1d,0x0)/USB(16,0)..BO

A little more information that may be of some help.
When first booting with the Slackware 15.0 DVD the final choice is as follows:
"detect/boot any installed operating system"

and when I make that selection I have the following screen shown

* Linux /boot/vmlinuz-generic
Linux /boot/vmlinuz-generic (single)
Linux /boot/vmlinuz-huge
Linux /boot/vmlinuz-huge (single)
Linux /boot/vmlinuz-generic-5.15.80
Linux /boot/vmlinuz-generic-5.15.80 (single)
Linux /boot/vmlinuz-huge-5.15.80
Linux /boot/vmlinuz-huge-5.15.80 (single)
(hd2,gpt1)/efi/Slackware/elilo.efi

===================================
If I select the last line (hd2,gpt1) for booting (which I believe is the
/dev/sda1 EF00 partition) - I get the following screen
==================================

/EndEntire
filepath: /ACPI(a03341d0,0)/PCI(2,8)/PCI(0,0)/SATA(1,ffff,0)/HD(1,800,50000,
dac5f514693040eb,2,2)
/File(\efi\Slackware)/File(elilo.efi)/EndEntire
error: attempt to read or write outside of partition

Press any key to continue...

==================================

This will only stay on screen for about 15 seconds and then goes back to
where I select the Linux OS to boot, but I think this may be the problem
but I am not sure what to do to repair this.

And finally a bit more data - I think from looking at the dmesg|tail that the problem is with the EF00 partition /dev/sda1.
I just do not have any idea of how to fix this without loading the system again (would really prefer not to do that).

The below is the gdisk /dev/sda1 "p" output and after that the dmesg | tail when I boot Linux /boot/vmlinuz-generic.
=============================================
bash-5.1# gdisk /dev/sda
GPT fdisk (gdisk) version 1.0.8

Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present

Found valid GPT with protective MBR; using GPT.

Command (? for help): P
Disk /dev/sda: 500118192 sectors, 238.5 GiB
Model: Micron_1100_MTFD
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): 5A2D8A72-2B6D-429C-BF7C-C8972A97B3E4
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 500118158
Partitions will be aligned on 2048-sector boundaries
Total free space is 2014 sectors (1007.0 KiB)

Number Start (sector) End (sector) Size Code Name
1 2048 329727 160.0 MiB EF00
2 329728 13961215 6.5 GiB 8200
3 13961216 500118158 231.8 GiB 8300

====================================================
dmesg | tail output
====================================================

bash-5.1# dmesg | tail
[ 173.754703] logitech-hidpp-device 0003:046D:4054.0005: HID++ 4.5 device
connected.
[ 251.269324] fuse: init (API version 7.34)
[ 564.717095] ntfs3: Max link count 4000
[ 564.717098] ntfs3: Enabled Linux POSIX ACLs support
[ 564.717099] ntfs3: Read-only LZX/Xpress compression included
[ 564.717514] ntfs3: Unknown parameter 'windows_names'
[ 611.485775] attempt to access beyond end of device
sda1: rw=524288, want=459818, limit=327680
[ 611.485790] attempt to access beyond end of device
sda1: rw=0, want=459818, limit=327680
bash-5.1#

========================================================

Also is there a site where I can download the kernel-generic-5.18.80, huge, and source?

Thanks all again..........

drumz - somehow I missed your input yesterday but I did everything you had posted and here are the outputs from the command
line you asked to see.
=======================================================
bash-5.1# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 238.5G 0 disk
??sda1 8:1 0 160M 0 part /boot/efi
??sda2 8:2 0 6.5G 0 part
??sda3 8:3 0 231.8G 0 part /drv_a3
sdb 8:16 0 931.5G 0 disk
??sdb1 8:17 0 931.5G 0 part /
sdc 8:32 0 2.7T 0 disk
??sdc1 8:33 0 2.7T 0 part /run/media/root/Elements
sr0 11:0 1 3.5G 0 rom
==============================
bash-5.1# mount
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
tmpfs on /run type tmpfs
(rw,nosuid,nodev,noexec,relatime,size=32768k,mode=755,inode64)
devtmpfs on /dev type devtmpfs
(rw,relatime,size=8192k,nr_inodes=1448602,mode=755,inode64)
/dev/sdb1 on / type ext4 (rw,relatime)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,inode64)
cgroup_root on /sys/fs/cgroup type tmpfs
(rw,relatime,size=8192k,mode=755,inode64)
cpuset on /sys/fs/cgroup/cpuset type cgroup (rw,relatime,cpuset)
cpu on /sys/fs/cgroup/cpu type cgroup (rw,relatime,cpu)
cpuacct on /sys/fs/cgroup/cpuacct type cgroup (rw,relatime,cpuacct)
blkio on /sys/fs/cgroup/blkio type cgroup (rw,relatime,blkio)
memory on /sys/fs/cgroup/memory type cgroup (rw,relatime,memory)
devices on /sys/fs/cgroup/devices type cgroup (rw,relatime,devices)
freezer on /sys/fs/cgroup/freezer type cgroup (rw,relatime,freezer)
net_cls on /sys/fs/cgroup/net_cls type cgroup (rw,relatime,net_cls)
perf_event on /sys/fs/cgroup/perf_event type cgroup (rw,relatime,perf_event)
net_prio on /sys/fs/cgroup/net_prio type cgroup (rw,relatime,net_prio)
pids on /sys/fs/cgroup/pids type cgroup (rw,relatime,pids)
misc on /sys/fs/cgroup/misc type cgroup (rw,relatime,misc)
/dev/sda3 on /drv_a3 type ext4 (rw,relatime)
/dev/sda1 on /boot/efi type vfat
(rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=
mixed,utf8,errors=remount-ro)
efivarfs on /sys/firmware/efi/efivars type efivarfs
(rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/elogind type cgroup
(rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/lib64/elogind/elogind-
cgroups-agent,name=elogind)
nfsd on /proc/fs/nfs type nfsd (rw,relatime)
nfsd on /proc/fs/nfsd type nfsd (rw,relatime)
tmpfs on /run/user/0 type tmpfs
(rw,nosuid,nodev,relatime,size=1160544k,nr_inodes=290136,mode=700,inode64)
gvfsd-fuse on /run/user/0/gvfs type fuse.gvfsd-fuse
(rw,nosuid,nodev,relatime,user_id=0,group_id=0)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
portal on /run/user/0/doc type fuse.portal
(rw,nosuid,nodev,relatime,user_id=0,group_id=0)
/dev/sdc1 on /run/media/root/Elements type fuseblk
(rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,
blksize=4096,uhelper=udisks2)
bash-5.1#
=========================================
bash-5.1# efibootmgr
BootCurrent: 0002
Timeout: 10 seconds
BootOrder: 0002,0000,0001,9999
Boot0000* Slackware
HD(1,GPT,14f5c5da-30c9-e640-9431-86e6a606c4ed,0x800,0x50000)/File(\EFI\Slackware
\elilo.efi)
Boot0001* Windows Boot Manager
HD(1,GPT,af1c99a6-a363-4762-95fe-ec55c77137ab,0x800,0x82000)/File(\EFI\Microsoft
\Boot\bootmgfw.efi)WINDOWS.........x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5
.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.4.7.9.5.}....................
Boot0002* Internal CD/DVD ROM Drive (UEFI)
PciRoot(0x0)/Pci(0x8,0x2)/Pci(0x0,0x1)/Sata(1,65535,0)/CDROM(1,0x2ed,0xb40)..BO
Boot9999* USB Drive (UEFI) PciRoot(0x0)/Pci(0x1d,0x0)/USB(16,0)..BO
/
bash-5.1# ls -l /dev/disk/by-partuuid/14f5c5da-30c9-e640-9431-86e6a606c4ed
lrwxrwxrwx 1 root root 10 Dec 1 11:08
/dev/disk/by-partuuid/14f5c5da-30c9-e640-9431-86e6a606c4ed -> ../../sda1

bash-5.1# ls -l /boot/efi/EFI/Slackware/elilo.conf
-rwxr-xr-x 1 root root 160 Nov 30 11:46 /boot/efi/EFI/Slackware/elilo.conf

It looks like your swap partition isn't active? Maybe that's because you booted from the CD/DVD instead of a normal boot?

Your EFI partition is correctly mounted at /boot/efi (also indicated in the below output), so that's good. Also the EFI parition is mounted as type "vfat", which is correct (I was confused by your dmesg output from an earlier post, but now I infer that the "ntfs" messages from dmesg pertain to /dev/sdc1).

I wonder if these messages:

mean your EFI partition somehow got corrupted. It is possible to just delete and recreate the partition, and then copy all the contents back to the new EFI partition without reinstalling Slackware (but first try to copy the existing contents of /boot/efi somewhere safe, especially since you have Windows boot loader!). I think if you do this you'd also have to use efibootmgr to register elilo with the boot manager again (because the partition uuids would change so the current entries in the UEFI boot manager would become invalid). Running eliloconfig would accomplish this. But if you boot into Windows (on /dev/sdc1) you'd also have to register the Windows Boot Loader with the boot manager as well. I think you could use efibootmgr to do this while booted into Slackware. You can look at your current efibootmgr output to see how the Windows boot loader is currently registered so you can reregister it after recreating your EFI partition.

Note: I actually haven't done this before, but I think it should work. Maybe someone else with more experience can confirm?

Or maybe just re-format the efi partion in vfat? (after copying its content)
I notice OP says it was a 256M partition, but fdisk says it's 160M ...

Sometimes vfat partitions are corrupted
You can check/recover with:

Thank you both for the advise........

I am not sure what is going on but I do believe something happened with /dev/sda1 which is the EF00 partition.

the output of df -h shows /dev/sda1 as 256M (see below).

My problem is that the files on /dev/sda1 can't be copied, I get error messages when I try and I have the
same problem on my /dev/sdb1/boot/efi/EFI/Slackware as those files can't be copied (again error messages).

I have tried to open those with both vim and nano (among others) and I get read errors (vim) or Input/Output errors
(nano).

I could use my Gparted disk and format the /dev/sda1 to vfat but not sure if I could then run the eliloconfig and
mkinitrd again or not.

I really did not want to reload the system as I have quite a bit under VirtualBox I do not want to lose.

Out of ideas on how to get the contents of /boot/efi/Slackware to someplace right now.
I know how to create the elilo.conf file but I am not sure how the elilo.efi is created (maybe from eliloconfig).
I can move or copy the vmlinuz-generic-5.15.80 to another location with the config files however.

Thanks again

thanks marav - when I try and run fsck.vfat /dev/sda1 I get an error message that says
"Seek to 272627200: Invalid argument"

Not exactly sure what that is trying to tell me.

eliloconfig install elilo.efi by copying /boot/elilo-x86_64.efi in /boot/efi/EFI/Slackware/elilo.efi
You could do it manually
Maybe they are other files in /boot/efi/EFI though if you use this EFI partition with other systems?

I don't see output of df -h...
In your previous posts both fdisk and lsblk report the partition size as 160M

edit, oh I saw it in previous page, so df reports size as 256M indeed, interesting...
Frankly at this point I would re-format /dev/sda1

Agreed. The Slackware portion of /boot/efi/EFI/Slackware can be easily recreated (without reinstalling all of Slackware) using eliloconfig.

But I don't know how to recreate /boot/efi/EFI/Microsoft. Do you by any chance have a backup?