Sorry cannot help much except you need to get it functioning off a real HD it supports before even considering moving to a CF. Since it came with a 720Mb HD best to try and get it working first.
From quick read it came out with a 120MB or 200MB HD originally and yes some Compaq's had that small hidden partition. Personally I loathe most early Compaq's for their horrid design and think you got one of those... sorry just rambling.

my03 wrote on 2023-12-08, 21:19:

Hi, […]
Show full quote

Hi,

i recently got hold of this model (its a dx4/100 w. 720MB hdd) and i could not get into any kind of bios on this thing (from what i've seen, F10 is required as soon as the cursor blinks on the top-right hand side of the screen, something it never does on this unit). I also now know that the bios is essentially replaced with some hidden partition software that supposedly boots up with F10 (i don't think i have this for reasons depicted later in this text).

So i googled around a bit and found the two diagnostic floppy images for these machines and wrote them to a pair of disks. When i now boot using the primary floppy, it tells me that i don't have any diagnostic partition available which is surprising as (from googling it again) this machine needs to have one in order to even boot up (??). If this is the case, its truly odd.

My goal here is to replace the mechanical drive with a CF/IDE one, but i'm not sure how large HDDs this machine can detect without having to resort to overlay-software (anyone knows?).

Which diagnostic SoftPaq disk set are you trying (your SP nos may vary depending on which version you downloaded)...

...Diagnostics/SETUP (SP1363) - https://ftp.zx.net.nz/pub/archive/ftp.hp.com/ … 1500/sp1363.exe

...Diagnostics/TEST (SP1456) - https://ftp.zx.net.nz/pub/archive/ftp.hp.com/ … 1500/sp1456.exe

Suppose another possibility, though not sure it applies here, is partitions do exist but have become corrupted...if it applies, maybe you could try this fix - https://ftp.zx.net.nz/pub/archive/ftp.hp.com/ … 1500/sp1454.exe

"Softpaq: SP1454
File Name: FIXPART.EXE
Title: Fix Partition Utility to Restore Primary Partition
Version: N/A

CATEGORY: Drivers / Miscellaneous

EFFECTIVE DATE: 15 December, 1995

PRODUCTS AFFECTED: Any Compaq product with a serial number range between x502xxxxxxxx and x547xxxxxxxx, except the Presario 7100 Family and the LTE 5000 Family

OPERATING SYSTEM: DOS 6.2 or Windows95

SYSTEM CONFIGURATION: DOS 6.2, DOS 6.2/Windows 3.1x or Windows 95

SUPERSEDES: None

DESCRIPTION: In rare instances on the above-referenced Compaq products, upgrading a hard drive system partition may result in the loss of the primary partition. The error "Missing Operating System" may appear upon rebooting after a system partition update.
- Use FIXPART.EXE (this SoftPaq) to recover from this error.
- To prevent the error on Compaq PC (non-server) products, obtain Compaq PC Diagnostics/TEST, Ver. 10.07 Rev B or higher (SoftPaq SP1456).
- To prevent the error on Compaq server products, obtain Compaq System Configuration Utility, Ver. 2.29 Rev C or higher (SoftPaq available in late-December 1995)

The FIXPART.EXE utility updates a corrupted file allocation table (FAT) using the backup copy of the FAT stored on the hard drive. The Operating System files are also replaced with the appropriate set of files for DOS 6.2 or Windows 95 systems. The utility will not correct partition information for units running Windows NT, OS/2, UNIX, or any other non-DOS operating system. Third-party utilities may be available to restore those operating systems; however, no third-party solution is either endorsed or supported by Compaq."

I do have a 430 which had the original installation with the hidden setup utility partition.

The bios then has the option to create the floppy disks in order to restore the hidden partition itself.

I can make a copy of the floppies later today or tomorrow.

Horun wrote on 2023-12-09, 05:23:

Sorry cannot help much except you need to get it functioning off a real HD it supports before even considering moving to a CF. Since it came with a 720Mb HD best to try and get it working first.
From quick read it came out with a 120MB or 200MB HD originally and yes some Compaq's had that small hidden partition. Personally I loathe most early Compaq's for their horrid design and think you got one of those... sorry just rambling.

Thx Horun for replying 😀

It had a (working) 720Mb drive with Win95 on it, but i wanted to "push it" a bit and get W98 SE onto it and at the same time make it a bit more quiet. I took what i had around (a Syba cf/ide adapter and a Sandisk Ultra II 2Gb CF-card) and it instantly recognized that it now had a disk connected with ~1.9Gb (when i ran the Comaq diagnostics that i found). But getting it all working 100% was a bit of a hassle (given that i wanted this special partition to be there as well).

I ended up starting msdos 6.22 install, but exiting with F3, then running fdisk to remove all existing partitions on the CF. Then i booted the diagnostics disk and let it create this special partition (and then copying over what it needed from Floppy #2). Booting msdos 6.22 again, i now could create a primary partition and assign the remainder of the space (funny enough, i now had a 1.7Gb FAT partition). I finalized the dos part by moving the system filies to the CF from the install disk. After popping out the CF and connecting it to my modern computer with a reader, i copied over the w98 install folder + some other utils.

Booting the CF again, i could now install W98 without issues. I finalized it by converting the HDD to fat32 (via the W98 "convert fat32" util) and it still worked after that, so i guess i'm all good now 😀

Oh, but when i see that blinking "square" in the right hand top corner, it always fails to load the diagnostics straight from the HDD for some reason. Maybe i have the wrong version of their diagnostics package for this machine?

PC Hoarder Patrol wrote on 2023-12-09, 09:16:

Which diagnostic SoftPaq disk set are you trying (your SP nos may vary depending on which version you downloaded)... […]
Show full quote

my03 wrote on 2023-12-08, 21:19:

Hi, […]
Show full quote

Hi,

i recently got hold of this model (its a dx4/100 w. 720MB hdd) and i could not get into any kind of bios on this thing (from what i've seen, F10 is required as soon as the cursor blinks on the top-right hand side of the screen, something it never does on this unit). I also now know that the bios is essentially replaced with some hidden partition software that supposedly boots up with F10 (i don't think i have this for reasons depicted later in this text).

So i googled around a bit and found the two diagnostic floppy images for these machines and wrote them to a pair of disks. When i now boot using the primary floppy, it tells me that i don't have any diagnostic partition available which is surprising as (from googling it again) this machine needs to have one in order to even boot up (??). If this is the case, its truly odd.

My goal here is to replace the mechanical drive with a CF/IDE one, but i'm not sure how large HDDs this machine can detect without having to resort to overlay-software (anyone knows?).

Which diagnostic SoftPaq disk set are you trying (your SP nos may vary depending on which version you downloaded)...

...Diagnostics/SETUP (SP1363) - https://ftp.zx.net.nz/pub/archive/ftp.hp.com/ … 1500/sp1363.exe

...Diagnostics/TEST (SP1456) - https://ftp.zx.net.nz/pub/archive/ftp.hp.com/ … 1500/sp1456.exe

Suppose another possibility, though not sure it applies here, is partitions do exist but have become corrupted...if it applies, maybe you could try this fix - https://ftp.zx.net.nz/pub/archive/ftp.hp.com/ … 1500/sp1454.exe

"Softpaq: SP1454
File Name: FIXPART.EXE
Title: Fix Partition Utility to Restore Primary Partition
Version: N/A

CATEGORY: Drivers / Miscellaneous

EFFECTIVE DATE: 15 December, 1995

PRODUCTS AFFECTED: Any Compaq product with a serial number range between x502xxxxxxxx and x547xxxxxxxx, except the Presario 7100 Family and the LTE 5000 Family

OPERATING SYSTEM: DOS 6.2 or Windows95

SYSTEM CONFIGURATION: DOS 6.2, DOS 6.2/Windows 3.1x or Windows 95

SUPERSEDES: None

DESCRIPTION: In rare instances on the above-referenced Compaq products, upgrading a hard drive system partition may result in the loss of the primary partition. The error "Missing Operating System" may appear upon rebooting after a system partition update.
- Use FIXPART.EXE (this SoftPaq) to recover from this error.
- To prevent the error on Compaq PC (non-server) products, obtain Compaq PC Diagnostics/TEST, Ver. 10.07 Rev B or higher (SoftPaq SP1456).
- To prevent the error on Compaq server products, obtain Compaq System Configuration Utility, Ver. 2.29 Rev C or higher (SoftPaq available in late-December 1995)

The FIXPART.EXE utility updates a corrupted file allocation table (FAT) using the backup copy of the FAT stored on the hard drive. The Operating System files are also replaced with the appropriate set of files for DOS 6.2 or Windows 95 systems. The utility will not correct partition information for units running Windows NT, OS/2, UNIX, or any other non-DOS operating system. Third-party utilities may be available to restore those operating systems; however, no third-party solution is either endorsed or supported by Compaq."

Thx heaps for those links PC Hoarder Patrol, much appreciated.

I looked at what i used (i.e what i found by chance on the net) and apparently i have something called "sp2054.exe" that will extract 2 image files that i can then write to floppy using imgburn. I have no clue if this is a proper version or not (i guess not as i had issues actually starting using the F10 at boot). When i boot disk #1, it actually takes me to the main menu and i can see all hardware, etc just fine. But i will now try the versions linked by you also.

mrfusion92 wrote on 2023-12-09, 10:14:

I do have a 430 which had the original installation with the hidden setup utility partition.

The bios then has the option to create the floppy disks in order to restore the hidden partition itself.

I can make a copy of the floppies later today or tomorrow.

This is highly appreciated mrfusion92 😀 But i now have a few options as linked above so i'll try them out first of all. But if possible, could i please ask of you to check what version you do have installed on your machine?

Thx