Guides, Reviews, RG351

RG351MP Custom Firmware Guide

by Russ

Wondering what custom firmware options you have available on the RG351MP? Yeah, me too. So let’s look at the four current operating systems you have available, and what that means for this little handheld console.

Timestamps:
00:00 introduction
01:14 clean and configured stock firmware
02:18 installing custom firmware
04:43 351ELEC
08:27 The Retro Arena
10:58 ArkOS
15:39 351Droid
17:01 summary and conclusion

Recommended microSD cards

128GB SanDisk Ultra and Samsung EVO Select microSD cards

For the RG351MP, custom firmware developers have found that microSD card brands that usually work well in other devices (PNY, MicroCenter) cause issues with this particular device. So the recommendation is to only use SanDisk or Samsung microSD cards in the RG351MP.

In general, I recommend the cards listed below, in order or preference. The prices fluctuate all the time, so keep an eye out for deals. In general, I would expect to pay $20 for a 128GB card and $30 for a 256GB card. A 128GB card will allow you to load EVERY 8-bit and 16-bit game out there, all of the arcade games that work, and quite a few PS1, Dreamcast, PSP, and Sega CD games (those systems have the largest file sizes). A 256GB card will allow you to store even more of those larger games. The RG351MP can use a separate card for the operating system; for that card, I recommend a 16GB card (usually around $7).

16GB cards: 
SanDisk Ultra  
SanDisk Industrial (more reliable but pricey)

128GB cards:
SanDisk Extreme
Samsung EVO Select
Samsung Pro Endurance (more reliable but pricey)
SanDisk Ultra

256GB cards:
Samsung EVO Select
SanDisk Ultra

Clean and configured stock firmware

Download it here

Added 21 additional themes. Some of them may not be compatible with certain systems, refer to my old RG351P themes guide for instructions on how to modify themes for this particular image. Other configuration updates include:

RetroArch: updated hotkeys, enabled overrides
Game Boy: added LCD ghosting, green color palate, removed LCD grid overlay, set scaling to core provided
Game Boy Color: removed LCD grid overlay, set scaling to core provided
Game Boy Advance: removed LCD grid overlay, set scaling to 3:2
N64: set Parallel as default core, 640×480 resolution, angrylion gfx plugin (adjust as needed)
Dreamcast: set 640×480 resolution
DraStic: reduced auto frameskip to 1 instead of 4 (press L3 to enter menu)
PPSSPP: adjusted scaling to auto scaling, set to 2x resolution with frameskip of 1 (press R3 to enter menu)

RetroArch hotkeys:

SELECT + X (or L3 + R3) = enter RetroArch menu
SELECT + R1 = save state
SELECT + L1 = load state
SELECT + R2 = fast forward (toggle)
SELECT + L2 = rewind (hold), must be turned on in settings
SELECT + Y = show framerate
SELECT + B = reset game

351ELEC

Download the beta version here

Be sure to check out the 351ELEC wiki guide for installation instructions and more helpful tips.

The Retro Arena

Download the latest release here

The Retro Arena and ArkOS are very similar, and TheRA developer recommends using the comprehensive ArkOS wiki page for installation and configuration instructions. Also check out the bottom of the Handheld Corner page for tips specific to TheRA.

Note that the SD2 cards between The Retro Arena and ArkOS are mostly cross-compatible. You may experience some unforeseen issues, but for the most part you can use the same card between the two.

Check out the Tech Toy Tinker Company YouTube channel for more showcases of The Retro Arena firmware.

ArkOS

Download the latest release here (look at the bottom of the page)

Note that ArkOS only releases downloadable builds every once in a while, but online updates are constant. So just download the latest firmware version listed on the frontpage, and then run the UPDATE tool to get the latest version.

Also be sure to check out the RG351MP FAQ section for more tips and tricks.

351Droid

Download the latest test build here

Be sure to check out the included guide PDF at the link above which will show you how to add the Google Play Store if you want (it’s pretty darn slow).

The 351Droid development team resides in the Retro Handhelds discord server, so for tips and advice I would recommend joining that server. This is the same server that hosts the Retro Game Corps discord space, so you should totally be on there anyway 🙂

18 thoughts on “RG351MP Custom Firmware Guide”

    1. No, but if you do use two, you can use the primary one for your firmware/os and the second one for your roms only so you don’t have to lose all your roms if you reformat the primary card.

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  3. Thanks! so, the clean and configured stock firmware, goes in the 16 GB SD card or how do I handle it?
    Then I assume by looking at your other videos that 351ELEC and the others can go in the secondary larger 128 or 256 SD card, right?

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    1. I ended up using a 256 card and writing 351 beta on it – there was an SSH process to make the second SD CARD work, so I was lazy and just used 1.

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  4. I’ve installed the new 351elec firmware for my RG351MP but the psp emulator is doing weird. All characters are rotated 90 degrees. Also the psx rearmed core does not play cd-music (tried everything). Duckstation is quite slow (which runs great on ArkOs) cd music is playing with duck station so no issues with my cue files. Are there any solutions for the problems I experience? Hope someone can help because it’s a great system

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  5. I am serious in purchasing an updated 351mp chip from you. I am frustrated trying to clone the updated version. Actually formatted the OS chip. I’m sad I did that. Please respond. I’ll pay plus shipping.

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  6. I did the whole installation process, but the PS1 emulator simply does not appear on the system… already checked the bios and the names of the folders and rooms and this all ok… any idea what may be wrong? Other games like GBA and Super Nintendo, work fine.

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    1. Patrick, if PS1 games are not showing up make sure that you unzipped the files first. Will not read if they are in .zip format. Once unzipped you should get some .bin and .cue files. I put them all into the psx folder on the machine and then it worked!

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  7. Can someone help me getting Wolf3d working on 351Elec? It starts shows a few spash screens then dies. And how do I get Duke3d and Prince of Persia to work, I think I have copied the files that it needs but it doesnt show up like the other games. (Doom/Tyrian is a blast on the device)

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  8. Thank you for posting this! I messed up my hotkey mapping and couldn’t figure out how to revert back to normal settings. Nearly every button was activating auto-save states lol. So installing stock firmware that’s pre-optimized really made things easier! I may try out the other firmware options as well. Cheers!

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  9. So let me get this straight.
    What do we install on the 16 gb sd card that already comes in the 351MP TF1 slot.
    And what do we install on our purchased 128 San disk ultra sad card that is to go in TF2 slot.
    I don’t want to mess this up😅

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  10. Do we have an updated video showing how to do all this?

    Would love a link, just got a RGB20S and it’s already failed SD card, I can’t save and a lot of games don’t load!

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  11. I’ve followed the steps and flashed a clean OS to my new SD Card and I get this on my boot screen!

    U-Boot 2017.09-g72b7650-dirty Jul 31 2021 01:43:12

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  12. I have R35S – powkiddy RGB20S clone, I was using ArkOs wersion 03/11/2023. When I update it to latest version my screen rotate and I don’t know how to fix it 😦 Is it possible ?

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    1. Yes, just copy the files from the boot file in the original card to the new boot folder. If the boot folder is hidden use ‘mini tool partition wizard’ to make it visible in Windows. If you don’t have the original boot folder, it has been uploaded on reddit in a guide on how to update r35s.

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  14. For anyone that has an RG351MP that crashes about 80% of the time at boot, I’ve got some news.

    I got my RG351MP in 2021. It worked OK with the stock OS, but every firmware I applied was complete frustration – 351Elec, AmberElec, JelOS – It would maybe boot 20% of the time and be fine after boot, and the other 80% would give a long scroll of text – a Linux core dump. 

    Changing SD Cards, running off of battery vs charging from the wall, it didn’t make a difference. I honestly should have returned it as a “defective unit”.

    Yesterday I decided to give the AmberElec prerelease firmware one last try, and my problems are completely gone. 10x boot on power, 10x boot on battery, 5x boot with different SD card. It’s just rock solid stability now. I rolled back to the AmberELEC 2023 release, and it crashed immediately.

    I popped into the AmberELEC discord and thanked the devs, who replied “We weren’t giving the RAM enough voltage” and “After we got provided a “bad” device it was only a matter of hours to fix it.”

    Anyway, for anyone who has an RG351MP collecting dust because it’s “broken”, give the AmberELEC prerelease another shot.

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