Category: Hardware

radtel RT-900 with CHIRP

I just got myself a radtel RT-900 2m/70cm radio to play around with as you can now pick those up on Amazon sometimes for as little as 30 bucks – which seems like a steal considering what you get. Even if you’re someone like me who wants to use it as just a handy little receiver.

The built-in BLE is a great way to program your radio without using a special cable (Kennwood-style serial programming cable) but the Chinese Android application… sucks, to put it mildly. I’m not even going to bother explaining all the ways it is terrible (as of early 2026) but after using it once for a couple minutes – just don’t bother. Because open-source to the rescue, there’s CHIRP.

Support for the RT-900 is currently still in Beta but worked just fine for me. My Ubuntu Notebook didn’t have the latest package in the repo yet but on my Arch-based Desktop it worked out of the box. Even using Bluetooth via python-ble-serial!

# yay -S python-ble-serial
# sudo ble-scan 
# ble-serial -d XX:XX:XX:XX:XX:XX (your radios ID you got from the scan)
 INFO | linux_pty.py: Port endpoint created on /tmp/ttyBLE -> /dev/pts/3
 INFO | ble_client.py: Receiver set up
 INFO | ble_client.py: Trying to connect with XX:XX:XX:XX:XX:XX: walkie-talkie
 INFO | ble_client.py: Device XX:XX:XX:XX:XX:XX connected
 INFO | ble_client.py: Found write-without-response characteristic 0000ffe1-0000-1000-8000-00805f9b34fb (H. 20)
 INFO | ble_client.py: Found notify characteristic 0000ffe1-0000-1000-8000-00805f9b34fb (H. 20)
 INFO | main.py: Running main loop!

Start CHIRP, Radio – Download from Radio – set “Port” to /tmp/ttyBLE, Vendor to Radtel and Model to RT-900 (not RT-900_BT for some reason. Maybe I have an earlier version where the Bluetooth was a retrofit?)

Adjust everything you want, Upload to Radio, done.

vcsu ERROR: Invalid IP address

If you run into the less than helpful message “ERROR: Invalid IP address” when trying to use the Virtual Connect Support Utility (vcsu for short) because you haven’t had to use that tool in a while, or ever: make sure you’re using the IP address and credentials of your Bladecenter OA and not the IP address of your VC device you want to update/check/whatever.

Turns out vcsu logs into your OA first, checks which VC interconnects are installed and goes from there. You’ll have to enter your VC login credentials at a later stage once the initial assesment is done.

Intel SSD Update ISO fails to boot

In case you’re trying to update the firmware on your Intel SSDs by using their handy dandy issdfut Version 3.0.7 or 3.0.8 ISO just to be greeted by an ISOLINUX error like

Failed to load ldlinux.c32
Boot failed: press a key to retry…

Chances are it’s because their ISO seems to be broken when booting using legacy BIOS mode. Switch to UEFI and it will most likely work the way it’s supposed to.
When you’re done, don’t forget to switch back to legacy BIOS if you installed your OS that way, otherwise it probably wont be able to boot.

Noisy Focusrite Scarlett and how to fix it

Having noise issues on your external USB audio interface when connected to a desktop PC and powered studio monitors? Chances are you’re having issues with your grounding… Make sure you are using balanced cables, meaning three wires (two phases + ground) to connect your speakers to the output of your interface.

I recently spent quite a few hours chasing down an extremely annoying crackling hum on my audio setup because of that. No ground loop, all devices connected to the same circuit, I even hooked everything up to an online UPS so I get perfect sine voltage but to no avail. When connected to my main workstation there was a noticeable and extremely annoying background noise on my monitors that wasn’t there when I plugged the Focusrite Scarlett 2i2 into my notebook or mobile phone via an USB OTG adapter. Heck, it wasn’t even there when I plugged it into an HP Z600 workstation that is sitting right beside my main computer, all connected to the same UPS, ethernet switches and whatnot…

Turns out I used unbalanced cables from the Scarlett to the monitors and apparently the MSI X99S mainboard (or maybe the power supply?) in my primary desktop computer has for some reason quite a bit of noise on the ground of the USB bus. Or something like that – I didn’t bother to get an oscilloscope to verify.

Swapping the cables from TS to proper TRS (tip-sleeve “mono” to tip-ring-sleeve “stereo” aka balanced) fixed it and everything sounds perfect, no matter what computer the interface is connected to.

HP ProLiant: 601 – diskette controller error, what it really means

I recently got this puzzling error message on an HP ProLiant Server: 601 – Diskette Controller Error with the system just stopping at the BIOS, no way to enter the maintenance menu or continue booting. Well that’s odd, I though… being a BL460c blade server. All the documentation I could find online suggested it’s a defective floppy drive, or loose cabling… which a blade server doesn’t have.

Ok, so it’s a legacy error message. Maybe the BBWC? Nope. Backplane module then? Nope. The disks? Nah. The fucking SD card module? Not even that… Well, let’s try a system reset them using the DIP switches. Nope. Switching to backup ROM and booting with that one… Doesn’t work either. Well, fuck. Remove all the mezzanine cards – basically the system stripped down to the bare minimum. Still the same error.

About three hours later… Being the only removable part left, I figured I remove the CMOS battery and check it while I’ve it remove. Turns out it’s dead. Replace it with a new CR2032 button cell and voila – system boots again as if nothing happened.

So there you go… 601 – diskette controller error apparently really means: your CMOS battery is dead, better replace it. Even though the documentation says otherwise.

Dear HP: Fuck you. I want those hours of my life back.