I know this thread is old; however I had a very similar problem at a HP MSR1002 4 AC Router (JG875A) router with firmware version R0306P30. (The router was new and original sealed; - I get it at eBay for an awesome good price.)
However, in my case the original installed firmware had simply no support for a web interface. The ip http enable command was not accepted and did nothing.
So, holy moly, HP really doesn’t make it easy, they made it in my case even more complex!
I had to go the harder way and update the firmware over a TFTP server client (Tftpd64 by Ph. Jounin). A long time ago I did this already at a 3Com 4200G Gigabit Switch. So after some testing I figured it out and it worked.
After the upgrade to firmware R0707P24 I was finally able to apply the ip http enable command and activate the web UI.
So my steps were:
A console connection to the MSR router was established and an IP address was defined. I decided me for the ip address 192.168.0.1 255.255.255.0 (at the Gigabit interface connected to the computer). Note, the port must be configured as port link-mode route and not as port link-mode bridge, otherwise no IP address can be applied.
As already described in the previous post, also a local-user admin with web and SSH permissions must be set. It is recommended to configure also the date & time manually.
The LAN port at the computer was manually set to 192.168.0.2 255.255.255.0 and the TFTP server client was installed and correctly configured (the firmware directory was selected).
Then I load the new firmware at the router CLI with:
tftp 192.168.0.2 get MSR100X-CMW710-R0707P24.ipe
The next step will extract several files to the internal flash and set the new firmware as default:
boot-loader file flash:/MSR100X-CMW710-R0707P24.ipe main
Both bootware, main and backup, were updated after the reboot.
Now I was able to activate the web UI with ip http enable and login. Because the internal flash was quite full, I downloaded the older firmware files to the computer and delete them in the flash. Also the *.ipe firmware file which is effectively a type of an archive can be deleted after the fw upgrade is processed. This will give additionaly some more free space.
That’s it, I hope this will help also other MSR users.